3.1.1. Origanum vulgare L.
Regarding the initial
O. vulgare essential oil, a total of 29 compounds were identified, with the main compounds being carvacrol (67.98%), p-cymene (12.29%),
trans-caryophyllene (5.19%), γ-terpinene (3.98%), caryophyllene oxide (1.96%), linalool (1.94%), α-terpinene (1.27%), limonene (ca. 1.00%), and thymol (0.73%). This composition indicates a high content of phenolic monoterpenes (81.08%). Additionally, smaller percentages of monoterpene and sesquiterpene hydrocarbons (6.57% and 5.92%, respectively), oxygenated monoterpenes (3.46%), and sesquiterpenes (2.05%) were present. These findings are consistent with essential oils derived from oregano subspecies found in Greece [
10].
During storage of the
Origanum aetheroleum at room temperature (ca. 23 °C without exposure to light for 6 months,
Table 1), a small percentage of volatile substances were lost from the sample within the first 10 days. Since GC-MS analysis examines the relative proportion of substances in the sample, the reduction or disappearance of these components leads to a relative increase in the percentage of the main substances, without an actual quantitative increase. Within Days 10 to 70, no significant alterations in the chemical profiles were observed. However, deterioration occurred between Days 80 and 130, as α-phellandrene, terpinen-4-ol, α-copaene, and humulene epoxide could no longer be detected. In the following days (140 to 170), traces of thymol and α-humulene were no longer detectable. As a result, the percentage of carvacrol at Day 170 increased from 67.98 (Day 1) to 79.03%, while the remaining detectable substances were α-terpinene, p-cymene, limonene, γ-terpinene, linalool,
trans-caryophyllene, and caryophyllene oxide.
Table 1.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
Table 1.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
No. | Compound | ΚΙ * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | α-Phellandrene | 1004 | 0.16 | 0.09 | 0.09 | 0.11 | 0.11 | 0.10 | 0.08 | 0.08 | 0.06 | - | - | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 1.27 | 0.84 | 0.92 | 0.84 | 0.92 | 0.80 | 0.78 | 0.75 | 0.51 | 0.40 | 0.43 | 0.39 | 0.54 | 0.57 | 0.59 | 0.62 | 0.49 | 0.43 |
4 | p-Cymene | 1022 | 12.29 | 12.61 | 14.22 | 13.07 | 13.16 | 12.56 | 13.1 | 13.58 | 13.62 | 12.47 | 12.17 | 11.85 | 13.73 | 14.4 | 14.96 | 15.36 | 13.29 | 12.33 |
5 | Limonene + 1,8 Cineol | 1042 | 1.37 | 1.28 | 1.42 | 1.30 | 1.36 | 1.27 | 1.25 | 1.20 | 0.83 | 0.66 | 0.69 | 0.65 | 0.74 | 0.78 | 0.78 | 0.81 | 0.74 | 0.71 |
6 | trans-β-Ocimene | 1047 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 3.98 | 3.62 | 3.85 | 3.56 | 3.69 | 3.36 | 3.45 | 3.34 | 2.63 | 2.16 | 2.23 | 2.10 | 2.55 | 2.63 | 2.63 | 2.71 | 2.33 | 2.06 |
8 | trans-Sabinene hydrate | 1069 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
9 | p-Mentha-3,8-diene | 1071 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
10 | Terpinolene | 1087 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | Linalool | 1099 | 1.94 | 1.52 | 1.49 | 1.53 | 1.61 | 1.42 | 1.42 | 1.32 | 0.93 | 0.69 | 0.73 | 0.67 | 0.89 | 0.97 | 0.93 | 0.97 | 0.80 | 0.71 |
12 | Borneol | 1156 | 0.53 | 0.4 | 0.37 | 0.40 | 0.43 | 0.36 | 0.38 | 0.33 | 0.23 | 0.16 | 0.19 | - | 0.23 | 0.25 | - | - | - | - |
13 | Terpinen-4-ol | 1169 | 0.46 | 0.38 | 0.35 | 0.37 | 0.39 | 0.34 | 0.34 | 0.30 | 0.20 | - | - | - | - | 0.23 | - | - | - | - |
14 | α-Terpineol | 1185 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Carvacrol methyl ether | 1237 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | trans-Citral (Geranial) | 1266 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Thymol | 1292 | 0.73 | 0.91 | 0.95 | 0.93 | 0.99 | 0.95 | 0.88 | 0.79 | 0.55 | 0.44 | 0.48 | 0.45 | 0.57 | 0.57 | - | - | - | - |
18 | Carvacrol | 1301 | 67.98 | 71.19 | 69.88 | 70.55 | 70.30 | 71.29 | 71.64 | 71.69 | 75.3 | 78.62 | 78.63 | 79.29 | 76.54 | 75.77 | 76.41 | 75.89 | 78.20 | 79.03 |
19 | Eugenol | 1354 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | α-Copaene | 1368 | 0.13 | 0.09 | 0.08 | 0.10 | 0.10 | 0.09 | 0.07 | 0.08 | - | - | - | - | - | - | - | - | - | - |
21 | Geranyl acetate | 1381 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | cis-Caryophyllene | 1397 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Caryophyllene | 1411 | 5.19 | 4.87 | 4.58 | 4.83 | 4.68 | 4.87 | 4.54 | 4.50 | 3.60 | 3.16 | 3.20 | 3.26 | 2.96 | 2.71 | 2.73 | 2.68 | 3.03 | 3.40 |
24 | Aromadendrene | 1438 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | α-Humulene | 1445 | 0.38 | 0.29 | 0.26 | 0.30 | 0.29 | 0.30 | 0.27 | 0.27 | 0.20 | 0.16 | 0.17 | 0.17 | 0.16 | 0.15 | - | - | - | - |
26 | β-Bisabolene | 1500 | 0.14 | 0.08 | - | 0.08 | 0.08 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - |
27 | δ-Cadinene | 1512 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | Caryophyllene oxide | 1576 | 1.96 | 1.68 | 1.53 | 1.71 | 1.74 | 1.78 | 1.65 | 1.70 | 1.34 | 1.07 | 1.07 | 1.16 | 1.08 | 0.97 | 0.97 | 0.96 | 1.12 | 1.33 |
29 | Humulene epoxide | 1590 | 0.09 | 0.07 | - | 0.07 | 0.07 | 0.07 | - | 0.06 | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 6.57 | 5.45 | 5.85 | 5.42 | 5.67 | 5.15 | 5.19 | 5.01 | 3.78 | 3.02 | 3.14 | 2.95 | 3.61 | 3.75 | 3.77 | 3.90 | 3.34 | 2.99 |
Oxygenated monoterpenes | 3.46 | 2.68 | 2.64 | 2.69 | 2.84 | 2.50 | 2.52 | 2.31 | 1.61 | 1.05 | 1.13 | 0.87 | 1.34 | 1.68 | 1.16 | 1.21 | 1.02 | 0.92 |
Phenolic monoterpenes | 81.08 | 84.71 | 85.05 | 84.55 | 84.45 | 84.8 | 85.62 | 86.06 | 89.47 | 91.53 | 91.28 | 91.59 | 90.84 | 90.74 | 91.37 | 91.25 | 91.49 | 91.36 |
Sesquiterpene hydrocarbons | 5.92 | 5.33 | 4.92 | 5.31 | 5.15 | 5.32 | 4.88 | 4.85 | 3.80 | 3.32 | 3.37 | 3.43 | 3.12 | 2.86 | 2.73 | 2.68 | 3.03 | 3.40 |
Oxygenated sesquiterpenes | 2.05 | 1.75 | 1.53 | 1.78 | 1.81 | 1.85 | 1.65 | 1.76 | 1.34 | 1.07 | 1.07 | 1.16 | 1.08 | 0.97 | 0.97 | 0.96 | 1.12 | 1.33 |
Total identified | 99.08 | 99.85 | 99.99 | 99.75 | 99.92 | 99.62 | 99.85 | 99.99 | 100.0 | 99.99 | 99.99 | 99.99 | 99.99 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
Table 2.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
Table 2.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
No. | Compound | ΚΙ * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | α-Phellandrene | 1004 | 0.16 | 0.11 | 0.08 | 0.08 | 0.10 | 0.07 | 0.07 | 0.08 | - | - | - | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 1.27 | 1.04 | 0.84 | 0.78 | 0.79 | 0.58 | 0.64 | 0.59 | 0.40 | 0.33 | 0.32 | 0.30 | 0.39 | 0.35 | 0.38 | 0.48 | 0.33 | 0.34 |
4 | p-Cymene | 1022 | 12.29 | 13.55 | 13.72 | 13.55 | 13.39 | 12.83 | 13.76 | 13.35 | 13.03 | 13.05 | 12.91 | 12.85 | 14.09 | 13.93 | 14.68 | 14.28 | 14.7 | 12.93 |
5 | Limonene + 1,8 Cineol | 1042 | 1.37 | 1.46 | 1.37 | 1.33 | 1.37 | 1.16 | 1.23 | 1.22 | 0.86 | 0.67 | 0.68 | 0.65 | 0.72 | 0.70 | 0.75 | 0.75 | 0.78 | 0.69 |
6 | trans-β-Ocimene | 1047 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 3.98 | 3.94 | 3.52 | 3.28 | 3.30 | 2.71 | 2.95 | 2.72 | 2.05 | 1.74 | 1.69 | 1.61 | 1.86 | 1.74 | 1.79 | 2.23 | 1.61 | 1.76 |
8 | trans-Sabinene hydrate | 1069 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
9 | p-Mentha-3,8-diene | 1071 | 0.07 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
10 | Terpinolene | 1087 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | Linalool | 1099 | 1.94 | 1.83 | 1.56 | 1.53 | 1.55 | 1.38 | 1.43 | 1.33 | 0.94 | 0.73 | 0.72 | 0.69 | 0.85 | 0.90 | 0.90 | 0.88 | 0.77 | 0.75 |
12 | Borneol | 1156 | 0.53 | 0.52 | 0.41 | 0.42 | 0.42 | 0.34 | 0.39 | 0.36 | 0.24 | 0.18 | 0.19 | - | - | 0.24 | - | - | - | - |
13 | Terpinen-4-ol | 1169 | 0.46 | 0.48 | 0.37 | 0.38 | 0.38 | 0.31 | 0.34 | 0.31 | 0.21 | - | - | - | - | - | - | - | - | - |
14 | α-Terpineol | 1185 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Carvacrol methyl ether | 1237 | 0.05 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | trans-Citral (Geranial) | 1266 | 0.04 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Thymol | 1292 | 0.73 | 1.08 | 0.92 | 0.95 | 0.97 | 0.80 | 0.92 | 0.85 | 0.62 | 0.48 | 0.48 | 0.49 | 0.56 | 0.64 | - | - | - | - |
18 | Carvacrol | 1301 | 67.98 | 68.31 | 69.98 | 70.34 | 70.66 | 72.26 | 71.32 | 72.1 | 76.54 | 78.53 | 78.68 | 79.02 | 77.4 | 77.8 | 77.72 | 77.49 | 77.47 | 79.12 |
19 | Eugenol | 1354 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | α-Copaene | 1368 | 0.13 | 0.10 | 0.10 | 0.10 | 0.09 | 0.08 | 0.07 | 0.07 | - | - | - | - | - | - | - | - | - | - |
21 | Geranyl acetate | 1381 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | cis-Caryophyllene | 1397 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Caryophyllene | 1411 | 5.19 | 4.66 | 4.45 | 4.38 | 4.32 | 4.09 | 3.86 | 3.74 | 3.02 | 2.54 | 2.52 | 2.48 | 2.37 | 2.11 | 2.14 | 2.67 | 2.39 | 2.72 |
24 | Aromadendrene | 1438 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | α-Humulene | 1445 | 0.38 | 0.30 | 0.27 | 0.28 | 0.27 | 0.25 | 0.23 | 0.22 | 0.16 | 0.14 | 0.14 | 0.14 | - | - | - | - | - | - |
26 | β-Bisabolene | 1500 | 0.14 | 0.10 | 0.08 | 0.08 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | δ-Cadinene | 1512 | 0.06 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | Caryophyllene oxide | 1575 | 1.96 | 1.91 | 2.02 | 2.21 | 2.18 | 2.46 | 2.40 | 2.40 | 1.92 | 1.61 | 1.67 | 1.77 | 1.75 | 1.59 | 1.64 | 1.22 | 1.95 | 1.69 |
29 | Humulene epoxide | 1590 | 0.09 | 0.08 | 0.08 | 0.09 | 0.08 | 0.09 | 0.09 | 0.09 | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 6.57 | 6.11 | 5.40 | 5.07 | 5.15 | 4.17 | 4.52 | 4.24 | 3.05 | 2.54 | 2.49 | 2.37 | 2.75 | 2.58 | 2.70 | 3.24 | 2.49 | 2.58 |
Oxygenated monoterpenes | 3.46 | 3.34 | 2.75 | 2.73 | 2.76 | 2.38 | 2.53 | 2.37 | 1.65 | 1.11 | 1.11 | 0.89 | 1.07 | 1.35 | 1.13 | 1.11 | 1.00 | 0.96 |
Phenolic monoterpenes | 81.08 | 82.98 | 84.62 | 84.84 | 85.02 | 85.89 | 86.00 | 86.3 | 90.19 | 92.06 | 92.07 | 92.36 | 92.05 | 92.37 | 92.4 | 91.77 | 92.17 | 92.05 |
Sesquiterpene hydrocarbons | 5.92 | 5.20 | 4.90 | 4.84 | 4.75 | 4.42 | 4.16 | 4.03 | 3.18 | 2.68 | 2.66 | 2.62 | 2.37 | 2.11 | 2.14 | 2.67 | 2.39 | 2.72 |
Oxygenated sesquiterpenes | 2.05 | 1.99 | 2.10 | 2.30 | 2.26 | 2.55 | 2.49 | 2.40 | 1.92 | 1.61 | 1.67 | 1.77 | 1.75 | 1.59 | 1.64 | 1.22 | 1.95 | 1.69 |
Total identified | 99.08 | 99.68 | 99.77 | 99.78 | 99.94 | 99.41 | 99.70 | 99.43 | 99.99 | 100 | 100 | 100 | 99.99 | 100 | 100 | 100 | 100 | 100 |
Table 3.
Chemical composition (%) of Origanum vulgare L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
Table 3.
Chemical composition (%) of Origanum vulgare L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
No. | Compounds | ΚΙ * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | α-Phellandrene | 1004 | 0.16 | 0.09 | 0.10 | 0.07 | 0.11 | 0.11 | 0.06 | 0.04 | - | 0.09 | 0.09 | 0.08 | 0.10 | 0.10 | 0.08 | 0.09 | - |
2 | δ-3-Carene | 1006 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 1.27 | 0.80 | 0.87 | 0.77 | 0.93 | 0.81 | 0.63 | 0.41 | 0.52 | 0.80 | 0.92 | 0.86 | 0.88 | 0.90 | 0.83 | 0.80 | 0.53 |
4 | p-Cymene | 1022 | 12.29 | 12.7 | 13.66 | 13.16 | 13.40 | 12.21 | 13.30 | 11.67 | 12.10 | 12.7 | 13.44 | 13.08 | 13.06 | 13.57 | 13.13 | 13.78 | 12.27 |
5 | Limonene + 1,8 Cineol | 1042 | 1.37 | 1.30 | 1.37 | 1.32 | 1.39 | 1.19 | 1.24 | 1.02 | 0.83 | 1.30 | 1.37 | 1.31 | 1.39 | 1.38 | 1.26 | 1.24 | 0.83 |
6 | trans-β-Ocimene | 1047 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 3.98 | 3.60 | 3.60 | 3.29 | 3.73 | 3.31 | 2.88 | 2.00 | 2.68 | 3.60 | 3.79 | 3.58 | 3.68 | 3.8 | 3.61 | 3.46 | 2.71 |
8 | trans-Sabinene hydrate | 1069 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
9 | p-Mentha-3,8-diene | 1071 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
10 | Terpinolene | 1087 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | Linalool | 1099 | 1.94 | 1.50 | 1.55 | 1.53 | 1.58 | 1.38 | 1.48 | 1.23 | 0.97 | 1.50 | 1.55 | 1.50 | 1.47 | 1.56 | 1.47 | 1.31 | 0.97 |
12 | Borneol | 1156 | 0.53 | 0.30 | 0.43 | 0.41 | 0.41 | 0.38 | 0.40 | 0.33 | 0.21 | 0.30 | 0.41 | 0.40 | 0.35 | 0.39 | 0.40 | 0.35 | 0.24 |
13 | Terpinen-4-ol | 1169 | 0.46 | 0.30 | 0.37 | 0.37 | 0.38 | 0.35 | 0.36 | 0.29 | 0.22 | 0.30 | 0.37 | 0.37 | 0.35 | 0.37 | 0.36 | 0.31 | 0.22 |
14 | α-Terpineol | 1185 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Carvacrol methyl ether | 1237 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | trans-Citral (Geranial) | 1266 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Thymol | 1292 | 0.73 | 0.90 | 0.93 | 0.94 | 0.94 | 2.28 | 1.03 | 5.10 | 0.59 | 0.9 | 0.91 | 0.92 | 0.89 | 1.01 | 0.92 | 0.83 | 0.59 |
18 | Carvacrol | 1301 | 67.98 | 71.00 | 70.04 | 70.79 | 70.08 | 70.71 | 71.35 | 71.6 | 76.69 | 71.00 | 69.83 | 70.79 | 71.27 | 70.46 | 71.16 | 71.31 | 76.36 |
19 | Eugenol | 1354 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | α-Copaene | 1368 | 0.13 | 0.10 | 0.10 | 0.09 | 0.09 | 0.09 | 0.09 | 0.07 | - | 0.10 | 0.09 | 0.09 | 0.08 | 0.09 | 0.08 | 0.07 | - |
21 | Geranyl acetate | 1381 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | cis-Caryophyllene | 1397 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Caryophyllene | 1411 | 5.19 | 4.80 | 4.58 | 4.50 | 4.72 | 4.42 | 3.88 | 3.05 | 3.81 | 4.80 | 4.84 | 4.78 | 4.67 | 4.63 | 4.67 | 4.52 | 3.80 |
24 | Aromadendrene | 1418 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | α-Humulene | 1445 | 0.38 | 0.20 | 0.28 | 0.28 | 0.29 | 0.26 | 0.24 | 0.19 | 0.21 | 0.20 | 0.29 | 0.29 | 0.28 | 0.28 | 0.28 | 0.26 | 0.21 |
26 | β-Bisabolene | 1500 | 0.14 | 0.08 | 0.08 | 0.07 | 0.07 | 0.07 | 0.06 | - | - | 0.08 | 0.07 | 0.07 | - | - | - | - | - |
27 | δ-Cadinene | 1512 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | Caryophyllene oxide | 1576 | 1.96 | 1.60 | 1.91 | 2.03 | 1.61 | 1.48 | 2.52 | 2.56 | 1.16 | 1.60 | 1.61 | 1.60 | 1.52 | 1.46 | 1.51 | 1.39 | 1.10 |
29 | Humulene epoxide | 1590 | 0.09 | 0.07 | 0.08 | 0.08 | 0.06 | 0.06 | 0.10 | 0.10 | - | 0.07 | 0.06 | 0.06 | - | - | - | - | - |
Monoterpene hydrocarbons | 6.57 | 5.40 | 5.53 | 5.05 | 5.74 | 5.06 | 4.44 | 3.16 | 3.78 | 5.40 | 5.76 | 5.44 | 5.63 | 5.77 | 5.40 | 5.22 | 3.82 |
Oxygenated monoterpenes | 3.46 | 2.49 | 2.76 | 2.71 | 2.79 | 2.47 | 2.61 | 2.16 | 1.65 | 2.49 | 2.74 | 2.66 | 2.59 | 2.73 | 2.61 | 2.34 | 1.68 |
Phenolic monoterpenes | 81.08 | 84.60 | 84.63 | 84.89 | 84.42 | 85.2 | 85.68 | 88.37 | 89.38 | 84.6 | 84.18 | 84.79 | 85.22 | 85.04 | 85.21 | 85.92 | 89.22 |
Sesquiterpene hydrocarbons | 5.92 | 5.18 | 5.04 | 4.94 | 5.17 | 4.84 | 4.27 | 3.31 | 4.02 | 5.18 | 5.29 | 5.23 | 5.03 | 5.00 | 5.03 | 4.85 | 4.01 |
Oxygenated sesquiterpenes | 2.05 | 1.67 | 1.99 | 2.11 | 1.67 | 1.54 | 2.62 | 2.66 | 1.16 | 1.67 | 1.67 | 1.66 | 1.52 | 1.46 | 1.51 | 1.39 | 1.10 |
Total identified | 99.08 | 99.34 | 99.95 | 99.7 | 99.79 | 99.11 | 99.62 | 99.66 | 99.99 | 99.34 | 99.64 | 99.78 | 99.99 | 100 | 99.76 | 99.72 | 99.83 |
Table 4.
Chemical composition (%) of Origanum vulgare L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
Table 4.
Chemical composition (%) of Origanum vulgare L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | ΚΙ * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | α-Phellandrene | 1004 | 0.16 | 0.09 | - | - | - | - | - | - | - | 0.08 | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 1.27 | 0.71 | 0.50 | 0.39 | 0.37 | 0.44 | 0.43 | 0.44 | 0.44 | 0.72 | 0.50 | 0.38 | 0.36 | 0.41 | 0.41 | 0.46 | 0.43 |
4 | p-Cymene | 1022 | 12.29 | 14.06 | 13.13 | 12.38 | 12.24 | 13.07 | 13.4 | 14.09 | 14.04 | 14.24 | 13.51 | 12.51 | 12.36 | 12.84 | 12.71 | 13.95 | 13.90 |
5 | Limonene + 1.8 Cineol | 1042 | 1.37 | 1.22 | 0.86 | 0.71 | 0.67 | 0.70 | 0.71 | 0.73 | 0.75 | 1.20 | 0.88 | 0.68 | 0.65 | 0.65 | 0.71 | 0.76 | 0.73 |
6 | trans-β-Ocimene | 1047 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 3.98 | 3.25 | 2.47 | 2.03 | 1.93 | 2.16 | 2.09 | 2.10 | 2.05 | 3.23 | 2.47 | 2.00 | 1.91 | 2.04 | 2.03 | 2.13 | 1.99 |
8 | trans-Sabinene hydrate | 1069 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
9 | p-Mentha-3.8-diene | 1071 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
10 | Terpinolene | 1087 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | Linalool | 1099 | 1.94 | 1.34 | 0.95 | 0.72 | 0.70 | 0.83 | 0.91 | 0.90 | 0.86 | 1.35 | 0.93 | 0.72 | 0.70 | 0.79 | 0.90 | 0.92 | 0.83 |
12 | Borneol | 1156 | 0.53 | 0.33 | 0.24 | 0.19 | - | - | - | - | - | 0.34 | 0.23 | 0.19 | - | - | - | - | - |
13 | Terpinen-4-ol | 1169 | 0.46 | 0.30 | 0.22 | - | - | - | - | - | - | 0.31 | 0.21 | - | - | - | - | - | - |
14 | α-Terpineol | 1185 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Carvacrol methyl ether | 1237 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | trans-Citral (Geranial) | 1266 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Thymol | 1292 | 0.73 | 0.76 | 0.59 | 0.48 | 0.48 | 0.54 | 0.61 | - | - | 0.81 | 0.58 | 0.48 | 0.47 | 0.50 | 0.68 | - | - |
18 | Carvacrol | 1301 | 67.98 | 71.68 | 75.9 | 78.69 | 79.14 | 78.01 | 78.09 | 77.97 | 77.91 | 71.47 | 75.62 | 78.69 | 79.15 | 78.46 | 78.8 | 78.01 | 78.26 |
19 | Eugenol | 1354 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | α-Copaene | 1368 | 0.13 | 0.07 | - | - | - | - | - | - | - | 0.07 | - | - | - | - | - | - | - |
21 | Geranyl acetate | 1381 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | cis-Caryophyllene | 1397 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Caryophyllene | 1411 | 5.19 | 4.11 | 3.47 | 2.97 | 2.95 | 2.86 | 2.51 | 2.50 | 2.58 | 4.11 | 3.42 | 2.95 | 2.92 | 2.81 | 2.54 | 2.54 | 2.55 |
24 | Aromadendrene | 1438 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | α-Humulene | 1445 | 0.38 | 0.24 | 0.19 | 0.16 | 0.16 | - | - | - | - | 0.24 | 0.19 | 0.16 | 0.15 | 0.16 | - | - | - |
26 | β-Bisabolene | 1500 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | δ-Cadinene | 1512 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | Caryophyllene oxide | 1576 | 1.96 | 1.72 | 1.48 | 1.28 | 1.36 | 1.39 | 1.23 | 1.26 | 1.37 | 1.76 | 1.46 | 1.24 | 1.32 | 1.34 | 1.22 | 1.23 | 1.31 |
29 | Humulene epoxide | 1590 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 6.57 | 4.90 | 3.57 | 2.92 | 2.77 | 3.09 | 3.02 | 3.05 | 3.02 | 4.87 | 3.59 | 2.86 | 2.73 | 2.91 | 2.94 | 3.12 | 2.93 |
Oxygenated monoterpenes | 3.46 | 2.34 | 1.67 | 1.12 | 0.90 | 1.04 | 1.12 | 1.12 | 1.09 | 2.36 | 1.63 | 1.11 | 0.90 | 0.99 | 1.11 | 1.15 | 1.05 |
Phenolic monoterpenes | 81.08 | 86.5 | 89.62 | 91.55 | 91.86 | 91.62 | 92.10 | 92.06 | 91.95 | 86.52 | 89.71 | 91.68 | 91.98 | 91.8 | 92.19 | 91.96 | 92.16 |
Sesquiterpene hydrocarbons | 5.92 | 4.42 | 3.66 | 3.13 | 3.11 | 2.86 | 2.51 | 2.50 | 2.58 | 4.42 | 3.61 | 3.11 | 3.07 | 2.97 | 2.54 | 2.54 | 2.55 |
Oxygenated sesquiterpenes | 2.05 | 1.72 | 1.48 | 1.28 | 1.36 | 1.39 | 1.23 | 1.26 | 1.37 | 1.76 | 1.46 | 1.24 | 1.32 | 1.34 | 1.22 | 1.23 | 1.31 |
Total identified | 99.08 | 99.88 | 100 | 100 | 100 | 100 | 99.98 | 99.99 | 100 | 99.93 | 100 | 100 | 99.99 | 100 | 100 | 100 | 100 |
Table 5.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers, and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
Table 5.
Chemical composition (%) of Origanum vulgare L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers, and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
| 4 °C Glass Tubes | 4 °C Metal | 4 °C Ampoules | −20 °C |
---|
Nο | Compound | ΚΙ | 1st | 30th | 60th | 90th | 120th | 150th | 180th | 180th | 180th | 180th |
---|
1 | α-Phellandrene | 1004 | 0.16 | 0.09 | 0.09 | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.02 | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 1.27 | 0.89 | 0.85 | 0.54 | 0.47 | 0.53 | 0.46 | 0.71 | 0.68 | 0.45 |
4 | p-Cymene | 1022 | 12.29 | 13.20 | 13.49 | 12.72 | 12.03 | 13.37 | 11.9 | 14.96 | 13.88 | 11.96 |
5 | Limonene + 1,8 Cineol | 1042 | 1.37 | 1.33 | 1.31 | 0.83 | 0.65 | 0.73 | 0.66 | 1.00 | 0.97 | 0.67 |
6 | trans-β-Ocimene | 1047 | 0.03 | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 3.98 | 3.68 | 3.70 | 2.70 | 2.41 | 2.47 | 2.36 | 3.00 | 3.00 | 2.20 |
8 | trans-Sabinene hydrate | 1069 | 0.02 | - | - | - | - | - | - | - | - | - |
9 | p-Mentha-3,8-diene | 1071 | 0.07 | - | - | - | - | - | - | - | - | - |
10 | Terpinolene | 1087 | 0.08 | - | - | - | - | - | - | - | - | - |
11 | Linalool | 1099 | 1.94 | 1.53 | 1.45 | 0.95 | 0.79 | 0.81 | 0.75 | 1.15 | 1.10 | 0.69 |
12 | Borneol | 1156 | 0.53 | 0.41 | 0.39 | 0.24 | - | - | - | 0.32 | 0.32 | - |
13 | Terpinen-4-ol | 1169 | 0.46 | 0.38 | 0.35 | 0.21 | - | - | - | 0.31 | 0.28 | - |
14 | α-Terpineol | 1185 | 0.05 | - | - | - | - | - | - | - | - | - |
15 | Carvacrol methyl ether | 1237 | 0.05 | - | - | - | - | - | - | - | - | - |
16 | trans-Citral (Geranial) | 1266 | 0.04 | - | - | - | - | - | - | - | - | - |
17 | Thymol | 1292 | 0.73 | 0.92 | 0.91 | 0.57 | 0.43 | - | - | 0.74 | 0.73 | - |
18 | Carvacrol | 1301 | 67.98 | 70.38 | 70.51 | 75.91 | 78.76 | 77.97 | 79.44 | 73.32 | 74.53 | 79.41 |
19 | Eugenol | 1354 | 0.03 | - | - | - | - | - | - | - | - | - |
20 | α-Copaene | 1368 | 0.13 | 0.09 | 0.08 | - | - | - | - | - | - | - |
21 | Geranyl acetate | 1381 | 0.01 | - | - | - | - | - | - | - | - | - |
22 | cis-Caryophyllene | 1397 | 0.01 | - | - | - | - | - | - | - | - | - |
23 | trans-Caryophyllene | 1411 | 5.19 | 4.90 | 4.74 | 3.76 | 3.27 | 3.16 | 3.42 | 3.13 | 3.29 | 3.58 |
24 | Aromadendrene | 1438 | 0.01 | - | - | - | - | - | - | - | - | - |
25 | α-Humulene | 1445 | 0.38 | 0.30 | 0.28 | 0.21 | 0.18 | - | - | 0.20 | 0.20 | - |
26 | β-Bisabolene | 1500 | 0.14 | 0.08 | - | - | - | - | - | - | - | - |
27 | δ-Cadinene | 1512 | 0.06 | - | - | - | - | - | - | - | - | - |
28 | Caryophyllene oxide | 1576 | 1.96 | 1.65 | 1.56 | 1.20 | 1.01 | 0.96 | 1.01 | 1.07 | 1.02 | 1.04 |
29 | Humulene epoxide | 1590 | 0.09 | 0.06 | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 6.57 | 5.59 | 5.56 | 3.82 | 3.34 | 3.51 | 3.28 | 4.41 | 4.36 | 3.12 |
Oxygenated monoterpenes | 3.46 | 2.72 | 2.58 | 1.65 | 0.99 | 1.03 | 0.95 | 2.08 | 1.99 | 0.89 |
Phenolic monoterpenes | 81.08 | 84.5 | 84.91 | 89.2 | 91.22 | 91.34 | 91.34 | 89.02 | 89.14 | 91.37 |
Sesquiterpene hydrocarbons | 5.92 | 5.37 | 5.10 | 3.97 | 3.45 | 3.16 | 3.42 | 3.33 | 3.49 | 3.58 |
Oxygenated sesquiterpenes | 2.05 | 1.71 | 1.56 | 1.20 | 1.01 | 0.96 | 1.01 | 1.07 | 1.02 | 1.04 |
Total identified | 99.08 | 99.89 | 99.71 | 99.84 | 100 | 100 | 100 | 99.91 | 100 | 100 |
Similar results were observed in the other experimental conditions (room temperature in direct sunlight, 35 °C, 45 °C, 4 °C, and −20 °C), indicating significant alterations in the essential oil composition under all conditions. In the experiment involving direct sunlight exposure for 6 months (
Table 2), the deterioration pattern was consistent with that observed between Days 10 to 70, 80 to 130, and 140 to 170. The components detected in the last measurement (Day 170) are the same as those of the previous experiment (α-terpinene, p-cymene, limonene, γ-terpinene, linalool,
trans-caryophyllene, and caryophyllene oxide), while the percentage of carvacrol, in this case, increases to 79.12%
Under high-temperature conditions (
Table 3 and
Table 4), the influence of the selected containers on the stability of the essential oil is revealed. The samples were placed for 3 months at a constant temperature of 35 °C and 45 °C in glass ampoules and in glass tubes with caps. The essential oil stored in ampoules exhibited increased stability compared to those in glass tubes despite the high temperature. For example, they managed to preserve α-humulene, borneol, terpinen-4-ol, and thymol for a duration of up to 3 months, while α-phellandrene, α-copaene, β-bisabolene, and α-humulene epoxide remained for a longer period compared to the samples in glass tubes. This difference is likely due to the reduced amount of air content in the ampoules, compared to the glass tubes, leading to lower oxygen availability, which is the main cause of oxidations and negative effects on the stability of essential oils experiments [
8].
Finally,
Table 5 exhibits the composition of the essential oil after being subjected to refrigeration (4 °C and −20 °C) for 6 months. The impact of container type (glass ampoules, glass tubes, and metal containers) on stability is evident here as well, as it is directly related to the oxygen availability in each case. In the glass ampoules with less air availability and in a well-sealed metal container with a plastic cap, more substances were preserved (borneol, terpinen-4-ol, thymol, and α-humulene). As a result, the percentage of carvacrol is significantly lower at Day 180 (73.32% for the metal container and 74.53% for the ampoule) compared to the glass tubes at 4 °C and −20 °C (79.44% and 79.41% respectively), in which fewer substances are retained. Furthermore, the availability of oxygen plays a crucial role in the stability of essential oils during their storage at low temperatures. This is in line with Henry’s law, which states that the solubility of oxygen is higher under such conditions experiments [
8].
Regarding the organoleptic characteristics of the essential oil, the photo-documentation revealed a color alteration from pale yellow to intense yellow during storage. Specifically, the change was intense at 35 °C and 45 °C as early as 45 days, while at the same thermal conditions, the color was better preserved in ampoules. Moreover, after 6 months of storage at 45 °C, the color of the sample turned to bright orange. It is noticeable that the storage in the glass tubes at 35 °C and 45 °C resulted in a significant decrease in the sample volumes, which implies extensive evaporation. Finally, under direct exposure to sunlight, the sample color slightly faded (
Figure 2).
It is worth mentioning that most essential oils are either completely transparent or pale yellow. The yellow color is caused by bisabolol,
trans-caryophyllene, carvone, linalool, or other yellowish compounds, and in some cases, the color derives from minor components that are <0.5% in the chemical load. Colored essential oil components are usually a consequence of the conjugation of double bonds, i.e., three or more double bonds in alternating sequences (e.g., eugenol) [
11,
12]. In addition, essential oil discoloration may result due to the oxidation/degradation of some ingredients, such as in the case of
trans-caryophyllene (yellow color), which is oxidized to caryophyllene oxide (colorless) [
13], resulting in the discoloration of the essential oils following their direct exposure to sunlight (see
Figure 2B), while other compounds may also contribute in this phenomenon.
3.1.2. Thymus vulgaris L.
As for the initial composition of
T. vulgaris essential oil, a total of 45 chemical substances were identified (
Table 6). The main compounds included thymol (55.77%), p-cymene (16.79%), γ-terpinene (6.32%), carvacrol (4.97%), linalool (3.72%),
trans-caryophyllene (2.48%), α-terpinene (2.03%), terpinen-4-ol (1.83%), and borneol (1.44%). The essential oil exhibited a high content of phenolic monoterpenes (78.27%), significant amounts of monoterpene hydrocarbons (8.97%) and oxygenated monoterpenes (7.97%), and smaller quantities of sesquiterpene hydrocarbons (3.57%) and oxygenated sesquiterpenes (0.59%). These findings are consistent with essential oils derived from
Thymus spp. growing wild in Greece [
14].
During the stability control at room temperature without light exposure (in glass tubes) (
Table 6), components with initial percentages lower than 0.10% were lost within the first 10 days. An exception was observed for
cis-β-ocimene, which initially increased over time, indicating its formation during the breakdown of other substances in the mixture before finally starting to decrease, as eventually its degradation took place. This is probably due to the degradation of linalool, which produces
cis-β-ocimene among others [
15]. The chemical composition remained relatively stable until Day 70, except for the loss of γ-cadinene on Day 20. From Days 80 to 100, significant changes occurred, with multiple components disappearing from the sample. These included α-phellandrene,
cis-sabinene hydrate, α-terpinolene,
trans-sabinene hydrate, camphor, α-terpineol, aromadendrene, α-humulene, viridiflorene, δ-cadinene, and spathulenol. Finally, after 170 days, only the main compounds and
cis-β-ocimene remained detectable, leading to an increase in thymol percentage from 58.56% in the initial sample to 68.03%.
Table 6.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
Table 6.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | α-Phellandrene | 1004 | 0.21 | 0.12 | 0.12 | 0.13 | 0.18 | 0.16 | 0.16 | 0.13 | 0.13 | 0.11 | - | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.07 | 0.07 | 0.07 | 0.07 | 0.08 | 0.07 | 0.07 | 0.07 | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 2.03 | 1.69 | 1.72 | 1.54 | 1.79 | 1.65 | 1.56 | 1.45 | 1.26 | 1.01 | 0.94 | 0.82 | 0.79 | 1.03 | 1.07 | 1.00 | 0.89 | 0.78 |
4 | p-Cymene | 1022 | 16.79 | 16.98 | 17.07 | 17.5 | 17.92 | 17.6 | 18.18 | 18.43 | 18.81 | 20.09 | 23.31 | 19.27 | 18.69 | 22.17 | 22.65 | 21.57 | 20.72 | 18.92 |
5 | cis-β-Ocimene | 1028 | 0.01 | 0.66 | 0.67 | 0.66 | 0.72 | 0.76 | 0.68 | 0.59 | 0.59 | 0.41 | 0.37 | 0.34 | 0.32 | 0.37 | 0.38 | 0.38 | 0.36 | 0.32 |
6 | trans-β-Ocimene | 1047 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 6.32 | 6.01 | 5.86 | 5.58 | 5.91 | 5.72 | 5.75 | 5.32 | 5.05 | 4.36 | 3.87 | 3.72 | 3.52 | 4.23 | 4.22 | 4.05 | 3.79 | 3.62 |
8 | cis-Sabinene hydrate | 1069 | 0.29 | 0.18 | 0.18 | 0.18 | 0.21 | 0.19 | 0.18 | 0.15 | 0.15 | 0.11 | - | - | - | - | - | - | - | - |
9 | α-Terpinolene | 1087 | 0.29 | 0.23 | 0.24 | 0.21 | 0.24 | 0.21 | 0.19 | 0.17 | 0.15 | 0.10 | - | - | - | - | - | - | - | - |
10 | 2,4-Decadienal | 1091 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | trans-Sabinene hydrate | 1094 | 0.04 | 0.06 | 0.06 | 0.08 | 0.08 | 0.08 | 0.08 | 0.06 | - | - | - | - | - | - | - | - | - | - |
12 | Linalool | 1101 | 3.72 | 3.37 | 3.36 | 3.17 | 3.39 | 3.21 | 3.22 | 2.98 | 2.84 | 2.21 | 1.76 | 1.82 | 1.76 | 2.16 | 2.10 | 2.05 | 1.95 | 1.87 |
13 | Camphor | 1134 | 0.09 | 0.06 | 0.28 | 0.18 | 0.17 | 0.06 | 0.09 | 0.06 | 0.04 | - | - | - | - | - | - | - | - | - |
14 | Borneol | 1157 | 1.44 | 1.14 | 1.21 | 1.08 | 1.15 | 1.15 | 1.11 | 0.99 | 0.91 | 0.69 | 0.51 | 0.59 | 0.57 | 0.67 | 0.64 | 0.65 | 0.60 | 0.63 |
15 | Terpinen-4-ol | 1169 | 1.83 | 1.05 | 1.12 | 1.01 | 1.09 | 1.06 | 1.02 | 0.93 | 0.85 | 0.64 | 0.47 | 0.53 | 0.54 | 0.62 | 0.59 | 0.59 | 0.56 | 0.58 |
16 | p-Cymen-8-ol | 1175 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | α-Terpineol | 1189 | 0.25 | 0.26 | 0.26 | 0.24 | 0.26 | 0.25 | 0.23 | 0.11 | - | - | - | - | - | - | - | - | - | - |
18 | Estragole | 1199 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | trans-Dihydro carvone | 1207 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Thymol, methyl ether | 1237 | 0.48 | 0.32 | 0.38 | 0.32 | 0.35 | 0.33 | 0.30 | 0.29 | 0.26 | 0.20 | 0.15 | 0.16 | 0.19 | 0.21 | 0.21 | - | - | - |
21 | Geranial | 1270 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | Carvone oxide | 1276 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | Thymol | 1292 | 55.77 | 58.56 | 57.86 | 59.19 | 57.75 | 58.82 | 58.87 | 59.67 | 61.15 | 63.97 | 63.89 | 67.61 | 68.18 | 63.67 | 63.38 | 64.75 | 66.11 | 68.03 |
24 | Carvacrol | 1301 | 4.97 | 5.58 | 5.53 | 5.45 | 5.27 | 5.49 | 5.24 | 5.27 | 4.84 | 4.11 | 3.25 | 3.57 | 3.81 | 3.51 | 3.56 | 3.70 | 3.75 | 3.93 |
25 | Thymol acetate | 1349 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Eugenol | 1351 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | Isoledene | 1365 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | α-Copaene | 1368 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Gurjunene | 1400 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | trans-Caryophyllene | 1410 | 2.48 | 2.12 | 2.15 | 2.07 | 2.02 | 1.99 | 1.96 | 1.95 | 1.75 | 1.50 | 1.26 | 1.34 | 1.39 | 1.18 | 1.20 | 1.26 | 1.27 | 1.32 |
31 | Aromandendrene | 1431 | 0.18 | 0.12 | 0.14 | 0.12 | 0.12 | 0.11 | 0.11 | 0.11 | 0.10 | - | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.15 | 0.09 | 0.10 | 0.11 | 0.11 | 0.12 | 0.08 | 0.11 | 0.12 | - | - | - | - | - | - | - | - | - |
33 | Alloaromadendrene | 1452 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | cis-Cadina-1(6),4-diene | 1462 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | γ-Muurolene | 1476 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | Viridiflorene | 1489 | 0.14 | 0.10 | 0.10 | 0.10 | 0.10 | 0.100 | 0.09 | 0.10 | 0.09 | - | - | - | - | - | - | - | - | - |
37 | α-Muurolene | 1494 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | γ-Cadinene | 1511 | 0.09 | 0.06 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
39 | trans-Calamenene | 1508 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
40 | δ-Cadinene | 1516 | 0.18 | 0.17 | 0.21 | 0.19 | 0.23 | 0.17 | 0.16 | 0.14 | 0.18 | 0.10 | - | - | - | - | - | - | - | - |
41 | Geranyl butanoate | 1555 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
42 | Spathulenol | 1571 | 0.15 | 0.09 | 0.11 | 0.10 | 0.10 | 0.09 | 0.08 | 0.09 | 0.08 | - | - | - | - | - | - | - | - | - |
43 | Caryophyllene oxide | 1576 | 0.43 | 0.30 | 0.34 | 0.30 | 0.29 | 0.30 | 0.31 | 0.34 | 0.32 | 0.26 | 0.22 | 0.23 | 0.24 | 0.18 | - | - | - | - |
44 | Geranyl 2-methyl butanoate | 1596 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
45 | Caryophylla-4(12),8(13)-dien-5α-ol | 1637 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 8.97 | 8.78 | 8.68 | 8.19 | 8.92 | 8.57 | 8.41 | 7.73 | 7.18 | 5.99 | 5.18 | 4.88 | 4.63 | 5.63 | 5.67 | 5.43 | 5.04 | 4.72 |
Oxygenated monoterpenes | 7.97 | 6.12 | 6.47 | 5.94 | 6.35 | 6.00 | 5.93 | 5.28 | 4.79 | 3.65 | 2.74 | 2.94 | 2.87 | 3.45 | 3.33 | 3.29 | 3.11 | 3.08 |
Phenolic monoterpenes | 78.27 | 81.44 | 80.84 | 82.46 | 81.29 | 82.24 | 82.59 | 83.66 | 85.06 | 88.37 | 90.60 | 90.61 | 90.87 | 89.56 | 89.8 | 90.02 | 90.58 | 90.88 |
Sesquiterpene hydrocarbons | 3.57 | 2.66 | 2.77 | 2.59 | 2.58 | 2.49 | 2.40 | 2.41 | 2.24 | 1.60 | 1.26 | 1.34 | 1.39 | 1.18 | 1.20 | 1.26 | 1.27 | 1.32 |
Oxygenated sesquiterpenes | 0.59 | 0.39 | 0.45 | 0.40 | 0.39 | 0.39 | 0.39 | 0.43 | 0.40 | 0.26 | 0.22 | 0.23 | 0.24 | 0.18 | - | - | - | - |
Total identified | 99.37 | 99.39 | 99.21 | 99.58 | 99.53 | 99.69 | 99.72 | 99.51 | 99.67 | 99.87 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Table 7.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
Table 7.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | α-Phellandrene | 1004 | 0.21 | 0.20 | 0.12 | 0.13 | 0.15 | 0.13 | 0.15 | 0.14 | 0.12 | 0.11 | - | - | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.07 | 0.09 | 0.08 | 0.07 | 0.07 | 0.05 | 0.07 | 0.07 | 0.06 | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 2.03 | 1.89 | 1.75 | 1.59 | 1.49 | 1.30 | 1.45 | 1.46 | 1.31 | 1.05 | 0.90 | 0.82 | 0.85 | 0.96 | 1.00 | 0.95 | 0.88 | 0.88 |
4 | p-Cymene | 1022 | 16.79 | 17.4 | 17.57 | 17.57 | 16.79 | 16.03 | 17.00 | 18.41 | 19.47 | 20.13 | 19.71 | 19.2 | 19.07 | 20.94 | 21.43 | 21.23 | 20.82 | 18.54 |
5 | cis-β-Ocimene | 1028 | 0.01 | 0.70 | 0.69 | 0.69 | 0.68 | 0.58 | 0.63 | 0.64 | 0.53 | 0.42 | 0.36 | 0.33 | 0.33 | 0.35 | 0.36 | 0.36 | 0.34 | 0.35 |
6 | trans-β-Ocimene | 1047 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 6.32 | 6.19 | 6.02 | 5.62 | 5.41 | 5.11 | 5.34 | 5.36 | 5.25 | 4.49 | 4.08 | 3.74 | 3.88 | 4.12 | 4.14 | 3.94 | 3.76 | 3.72 |
8 | cis-Sabinene hydrate | 1069 | 0.29 | 0.20 | 0.19 | 0.18 | 0.17 | 0.17 | 0.16 | 0.16 | 0.14 | 0.11 | - | - | - | - | - | - | - | - |
9 | α-Terpinolene | 1087 | 0.29 | 0.27 | 0.24 | 0.21 | 0.19 | 0.17 | 0.17 | 0.17 | 0.16 | 0.10 | - | - | - | - | - | - | - | - |
10 | 2,4-Decadienal | 1091 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | trans-Sabinene hydrate | 1094 | 0.04 | 0.07 | 0.07 | 0.08 | 0.08 | 0.07 | 0.07 | 0.06 | - | - | - | - | - | - | - | - | - | - |
12 | Linalool | 1101 | 3.72 | 3.57 | 3.34 | 3.12 | 2.85 | 3.16 | 2.92 | 2.93 | 2.84 | 2.30 | 1.84 | 1.81 | 1.91 | 2.16 | 2.12 | 1.99 | 1.93 | 1.93 |
13 | Camphor | 1134 | 0.09 | 0.06 | 0.06 | 0.18 | 0.17 | 0.05 | 0.08 | 0.05 | 0.05 | - | - | - | - | - | - | - | - | - |
14 | Borneol | 1157 | 1.44 | 1.32 | 1.19 | 1.08 | 1.00 | 1.08 | 0.99 | 0.99 | 0.88 | 0.73 | 0.59 | 0.59 | 0.62 | 0.67 | 0.65 | 0.62 | 0.59 | 0.64 |
15 | Terpinen-4-ol | 1169 | 1.83 | 1.16 | 1.09 | 1.00 | 0.94 | 1.01 | 0.93 | 0.93 | 0.84 | 0.67 | 0.53 | 0.53 | 0.58 | 0.63 | 0.61 | 0.58 | 0.55 | 0.60 |
16 | p-Cymen-8-ol | 1175 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | α-Terpineol | 1189 | 0.25 | 0.30 | 0.24 | 0.24 | 0.24 | 0.24 | 0.11 | 0.11 | 0.10 | - | - | - | - | - | - | - | - | - |
18 | Estragole | 1199 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | trans-Dihydro carvone | 1207 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Thymol, methyl ether | 1237 | 0.48 | 0.36 | 0.35 | 0.31 | 0.28 | 0.10 | 0.28 | 0.28 | 0.26 | 0.21 | 0.21 | 0.16 | 0.20 | 0.22 | 0.21 | 0.20 | - | - |
21 | Geranial | 1270 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | Carvone oxide | 1276 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | Thymol | 1292 | 55.77 | 56.88 | 57.72 | 59.47 | 61.91 | 61.30 | 62.11 | 60.47 | 60.49 | 63.52 | 66.62 | 67.65 | 67.23 | 65.07 | 64.59 | 65.1 | 66.08 | 68.01 |
24 | Carvacrol | 1301 | 4.97 | 5.58 | 5.54 | 5.23 | 4.87 | 5.41 | 4.70 | 4.83 | 4.73 | 4.10 | 3.54 | 3.58 | 3.76 | 3.61 | 3.62 | 3.70 | 3.72 | 3.90 |
25 | Thymol acetate | 1349 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Eugenol | 1351 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | Isoledene | 1365 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | α-Copaene | 1368 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Gurjunene | 1400 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | trans-Caryophyllene | 1410 | 2.48 | 2.13 | 2.12 | 1.98 | 1.80 | 2.14 | 1.77 | 1.83 | 1.80 | 1.60 | 1.39 | 1.38 | 1.37 | 1.26 | 1.27 | 1.32 | 1.33 | 1.43 |
31 | Aromandendrene | 1431 | 0.18 | 0.13 | 0.12 | 0.11 | 0.10 | 0.12 | 0.10 | 0.12 | 0.10 | - | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.15 | 0.11 | 0.10 | 0.11 | 0.11 | 0.10 | 0.08 | 0.07 | 0.10 | - | - | - | - | - | - | - | - | - |
33 | Alloaromadendrene | 1452 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | cis-Cadina-1(6),4-diene | 1462 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | γ-Muurolene | 1476 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | Viridiflorene | 1489 | 0.14 | 0.11 | 0.10 | 0.09 | 0.08 | 0.10 | 0.08 | 0.09 | 0.09 | - | - | - | - | - | - | - | - | - |
37 | α-Muurolene | 1494 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | γ-Cadinene | 1511 | 0.09 | 0.06 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
39 | trans-Calamenene | 1515 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
40 | δ-Cadinene | 1516 | 0.18 | 0.17 | 0.18 | 0.18 | 0.23 | 0.27 | 0.16 | 0.20 | 0.13 | 0.10 | - | - | - | - | - | - | - | - |
41 | Geranyl butanoate | 1555 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
42 | Spathulenol | 1571 | 0.15 | 0.10 | 0.12 | 0.09 | 0.09 | 0.09 | 0.07 | 0.07 | 0.08 | - | - | - | - | - | - | - | - | - |
43 | Caryophyllene oxide | 1576 | 0.43 | 0.30 | 0.30 | 0.28 | 0.25 | 0.32 | 0.26 | 0.28 | 0.30 | 0.23 | 0.23 | 0.19 | 0.19 | - | - | - | - | - |
44 | Geranyl 2-methyl butanoate | 1596 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
45 | Caryophylla-4(12),8(13)-dien-5α-ol | 1637 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 8.97 | 9.34 | 8.90 | 8.31 | 7.99 | 7.34 | 7.81 | 7.84 | 7.43 | 6.17 | 5.34 | 4.89 | 5.06 | 5.43 | 5.50 | 5.25 | 4.98 | 4.95 |
Oxygenated monoterpenes | 7.97 | 6.68 | 6.18 | 5.88 | 5.45 | 5.78 | 5.26 | 5.23 | 4.85 | 3.81 | 2.96 | 2.93 | 3.11 | 3.46 | 3.38 | 3.19 | 3.07 | 3.17 |
Phenolic monoterpenes | 78.27 | 80.22 | 81.18 | 82.58 | 83.85 | 82.84 | 84.09 | 83.99 | 84.95 | 87.96 | 90.08 | 90.59 | 90.26 | 89.84 | 89.85 | 90.23 | 90.62 | 90.45 |
Sesquiterpene hydrocarbons | 3.57 | 2.71 | 2.68 | 2.47 | 2.32 | 2.73 | 2.19 | 2.31 | 2.22 | 1.70 | 1.39 | 1.38 | 1.37 | 1.26 | 1.27 | 1.32 | 1.33 | 1.43 |
Oxygenated sesquiterpenes | 0.59 | 0.40 | 0.42 | 0.37 | 0.34 | 0.41 | 0.33 | 0.35 | 0.38 | 0.23 | 0.23 | 0.19 | 0.19 | - | - | - | - | - |
Total identified | 99.37 | 99.35 | 99.36 | 99.61 | 99.95 | 99.1 | 99.68 | 99.52 | 99.83 | 99.87 | 100 | 99.98 | 99.99 | 99.99 | 100 | 99.99 | 100 | 100 |
Table 8.
Chemical composition (%) of Thymus vulgaris L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
Table 8.
Chemical composition (%) of Thymus vulgaris L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | α-Phellandrene | 1004 | 0.21 | 0.12 | 0.09 | 0.15 | 0.16 | 0.15 | 0.17 | 0.16 | 0.14 | 0.13 | 0.05 | 0.15 | 0.16 | 0.18 | 0.17 | 0.16 | 0.15 |
2 | δ-3-Carene | 1006 | 0.07 | 0.06 | 0.07 | 0.07 | 0.07 | 0.07 | 0.07 | 0.07 | 0.06 | 0.08 | 0.07 | 0.07 | 0.07 | 0.07 | 0.07 | 0.07 | 0.06 |
3 | α-Terpinene | 1012 | 2.03 | 1.57 | 1.48 | 1.70 | 1.57 | 1.57 | 1.58 | 1.56 | 1.37 | 1.80 | 0.88 | 1.75 | 1.64 | 1.68 | 1.60 | 1.54 | 1.39 |
4 | p-Cymene | 1022 | 16.79 | 16.30 | 18.29 | 17.36 | 16.15 | 16.59 | 17.18 | 18.45 | 18.62 | 17.38 | 19.57 | 17.49 | 16.96 | 17.37 | 16.26 | 18.25 | 18.62 |
5 | cis-β-Ocimene | 1028 | 0.01 | 0.67 | 0.67 | 0.68 | 0.69 | 0.63 | 0.64 | 0.66 | 0.53 | 0.73 | 0.65 | 0.68 | 0.72 | 0.71 | 0.65 | 0.62 | 0.51 |
6 | trans-β-Ocimene | 1047 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 6.32 | 5.84 | 4.83 | 5.99 | 5.89 | 5.68 | 5.97 | 6.05 | 5.79 | 6.35 | 2.89 | 6.12 | 5.96 | 6.21 | 5.91 | 5.9 | 5.82 |
8 | cis-Sabinene hydrate | 1069 | 0.29 | 0.18 | 0.18 | 0.18 | 0.18 | 0.18 | 0.17 | 0.17 | 0.14 | 0.20 | 0.17 | 0.18 | 0.18 | 0.19 | 0.16 | 0.15 | 0.13 |
9 | α-Terpinolene | 1087 | 0.29 | 0.23 | 0.22 | 0.22 | 0.20 | 0.20 | 0.19 | 0.18 | 0.17 | 0.25 | 0.22 | 0.24 | 0.20 | 0.21 | 0.20 | 0.14 | 0.17 |
10 | 2,4-Decadienal | 1091 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | trans-Sabinene hydrate | 1094 | 0.04 | 0.06 | 0.07 | 0.07 | 0.09 | 0.07 | 0.06 | 0.08 | - | 0.08 | 0.07 | 0.06 | 0.08 | 0.08 | 0.07 | 0.04 | - |
12 | Linalool | 1101 | 3.72 | 3.34 | 3.28 | 3.14 | 3.11 | 3.13 | 3.03 | 3.05 | 2.87 | 3.42 | 3.40 | 3.32 | 3.09 | 3.23 | 3.04 | 2.87 | 2.83 |
13 | Camphor | 1134 | 0.09 | 0.14 | 0.08 | 0.08 | 0.19 | 0.19 | 0.05 | 0.17 | 0.05 | 0.24 | 0.27 | 0.27 | 0.19 | 0.20 | 0.08 | 0.08 | 0.05 |
14 | Borneol | 1157 | 1.44 | 1.15 | 1.12 | 1.08 | 1.11 | 1.14 | 1.00 | 1.01 | 0.88 | 1.19 | 1.25 | 1.25 | 1.08 | 1.13 | 1.02 | 0.96 | 0.91 |
15 | Terpinen-4-ol | 1169 | 1.83 | 1.08 | 1.05 | 1.01 | 1.03 | 1.06 | 0.96 | 0.95 | 0.86 | 1.11 | 1.11 | 1.10 | 1.03 | 1.04 | 0.98 | 0.90 | 0.87 |
16 | p-Cymen-8-ol | 1175 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | α-Terpineol | 1189 | 0.25 | 0.27 | 0.27 | 0.24 | 0.23 | 0.26 | 0.12 | - | - | 0.26 | 0.27 | 0.26 | 0.22 | 0.23 | 0.11 | - | - |
18 | Estragole | 1199 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | trans-Dihydro carvone | 1207 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Thymol, methyl ether | 1237 | 0.48 | 0.35 | 0.35 | 0.33 | 0.30 | 0.30 | 0.29 | 0.28 | 0.25 | 0.34 | 0.34 | 0.37 | 0.30 | 0.31 | 0.29 | 0.26 | 0.26 |
21 | Geranial | 1270 | 0.07 | 0.06 | 0.05 | - | - | - | - | - | - | 0.08 | - | - | - | - | - | - | - |
22 | Carvone oxide | 1276 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | Thymol | 1292 | 55.77 | 59.16 | 58.84 | 59.15 | 60.67 | 60.1 | 60.89 | 59.14 | 60.72 | 57.29 | 58.88 | 57.38 | 59.65 | 58.8 | 61.37 | 60.51 | 60.36 |
24 | Carvacrol | 1301 | 4.97 | 5.58 | 5.49 | 5.11 | 5.26 | 5.27 | 4.84 | 4.93 | 4.75 | 5.55 | 5.77 | 5.52 | 5.27 | 5.18 | 4.99 | 4.72 | 4.77 |
25 | Thymol acetate | 1349 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Eugenol | 1351 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | Isoledene | 1365 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | α-Copaene | 1368 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Gurjunene | 1400 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | trans-Caryophyllene | 1410 | 2.48 | 2.17 | 1.88 | 2.01 | 1.96 | 1.96 | 1.87 | 1.93 | 1.82 | 2.06 | 1.34 | 2.12 | 1.97 | 1.96 | 1.87 | 1.83 | 1.80 |
31 | Aromandendrene | 1431 | 0.18 | 0.12 | 0.12 | 0.11 | 0.11 | 0.11 | 0.10 | 0.10 | 0.10 | 0.12 | 0.13 | 0.14 | 0.10 | 0.11 | 0.10 | 0.09 | 0.10 |
32 | α-Humulene | 1445 | 0.15 | 0.11 | 0.08 | 0.13 | 0.13 | 0.13 | 0.10 | 0.10 | 0.10 | 0.10 | 0.08 | 0.14 | 0.11 | 0.07 | 0.11 | 0.07 | 0.11 |
33 | Alloaromadendrene | 1452 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | cis-Cadina-1(6),4-diene | 1462 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | γ-Muurolene | 1476 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | Viridiflorene | 1489 | 0.14 | 0.10 | 0.09 | 0.10 | 0.09 | 0.09 | 0.09 | 0.09 | 0.09 | 0.10 | 0.07 | 0.10 | 0.09 | 0.09 | 0.09 | 0.09 | 0.09 |
37 | α-Muurolene | 1494 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | γ-Cadinene | 1511 | 0.09 | 0.06 | 0.06 | 0.05 | - | - | - | - | - | 0.06 | 0.06 | 0.07 | - | - | - | - | - |
39 | trans-Calamenene | 1515 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
40 | δ-Cadinene | 1516 | 0.18 | 0.19 | 0.16 | 0.21 | 0.20 | 0.21 | 0.14 | 0.21 | 0.15 | 0.17 | 0.21 | 0.23 | 0.22 | 0.20 | 0.15 | 0.17 | 0.18 |
41 | Geranyl butanoate | 1555 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
42 | Spathulenol | 1571 | 0.15 | 0.11 | 0.09 | 0.10 | 0.08 | 0.09 | 0.07 | 0.07 | 0.08 | 0.10 | 0.10 | 0.12 | 0.08 | 0.09 | 0.08 | 0.06 | 0.08 |
43 | Caryophyllene oxide | 1576 | 0.43 | 0.34 | 0.49 | 0.28 | 0.26 | 0.3 | 0.26 | 0.27 | 0.27 | 0.30 | 1.08 | 0.32 | 0.26 | 0.26 | 0.26 | 0.25 | 0.26 |
44 | Geranyl 2-methyl butanoate | 1596 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
45 | Caryophylla-4(12),8(13)-dien-5α-ol | 1637 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 8.97 | 8.49 | 7.36 | 8.81 | 8.58 | 8.30 | 8.62 | 8.68 | 8.06 | 9.34 | 4.76 | 9.01 | 8.75 | 9.06 | 8.60 | 8.43 | 8.10 |
Oxygenated monoterpenes | 7.97 | 6.28 | 6.10 | 5.80 | 5.94 | 6.03 | 5.39 | 5.43 | 4.80 | 6.58 | 6.54 | 6.44 | 5.87 | 6.00 | 5.46 | 5.00 | 4.90 |
Phenolic monoterpenes | 78.27 | 81.39 | 82.97 | 81.95 | 82.38 | 82.26 | 83.2 | 82.8 | 84.34 | 80.56 | 84.56 | 80.76 | 82.18 | 81.66 | 82.91 | 83.74 | 84.01 |
Sesquiterpene hydrocarbons | 3.57 | 2.75 | 2.39 | 2.61 | 2.36 | 2.50 | 2.30 | 2.33 | 2.26 | 2.61 | 1.89 | 2.80 | 2.38 | 2.43 | 2.32 | 2.25 | 2.28 |
Oxygenated sesquiterpenes | 0.59 | 0.45 | 0.58 | 0.38 | 0.34 | 0.39 | 0.33 | 0.34 | 0.35 | 0.40 | 1.18 | 0.44 | 0.34 | 0.35 | 0.34 | 0.31 | 0.34 |
Total identified | 99.37 | 99.36 | 99.4 | 99.55 | 99.73 | 99.48 | 99.84 | 99.68 | 99.81 | 99.49 | 98.93 | 99.45 | 99.63 | 99.6 | 99.63 | 99.73 | 99.52 |
Table 9.
Chemical composition (%) of Thymus vulgaris L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
Table 9.
Chemical composition (%) of Thymus vulgaris L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | α-Phellandrene | 1004 | 0.21 | 0.13 | 0.12 | - | - | - | - | - | - | 0.14 | 0.12 | - | - | - | - | - | - |
2 | δ-3-Carene | 1006 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 2.03 | 1.36 | 1.08 | 0.87 | 0.85 | 0.87 | 1.00 | 1.03 | 0.99 | 1.34 | 1.08 | 0.87 | 0.85 | 0.88 | 1.00 | 1.04 | 0.98 |
4 | p-Cymene | 1022 | 16.79 | 19.53 | 19.8 | 19.56 | 19.09 | 18.82 | 20.87 | 21.65 | 20.98 | 19.02 | 19.88 | 19.38 | 19.19 | 18.83 | 21.13 | 21.44 | 20.97 |
5 | cis-β-Ocimene | 1028 | 0.01 | 0.58 | 0.43 | 0.33 | 0.33 | 0.32 | 0.36 | 0.35 | 0.39 | 0.62 | 0.42 | 0.34 | 0.33 | 0.33 | 0.35 | 0.39 | 0.37 |
6 | trans-β-Ocimene | 1047 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 6.32 | 5.25 | 4.61 | 3.88 | 3.80 | 3.89 | 4.14 | 4.14 | 4.02 | 5.27 | 4.62 | 3.86 | 3.79 | 3.89 | 4.15 | 4.11 | 3.87 |
8 | cis-Sabinene hydrate | 1069 | 0.29 | 0.15 | 0.11 | - | - | - | - | - | - | 0.15 | 0.11 | - | - | - | - | - | - |
9 | α-Terpinolene | 1087 | 0.29 | 0.15 | 0.13 | - | - | - | - | - | - | 0.15 | 0.11 | - | - | - | - | - | - |
10 | 2,4-Decadienal | 1091 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | trans-Sabinene hydrate | 1094 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
12 | Linalool | 1101 | 3.72 | 2.79 | 2.37 | 1.82 | 1.82 | 1.90 | 2.14 | 2.08 | 2.01 | 2.76 | 2.29 | 1.81 | 1.83 | 1.92 | 2.16 | 2.10 | 1.96 |
13 | Camphor | 1134 | 0.09 | - | - | - | - | - | - | - | - | 0.15 | - | - | - | - | - | - | - |
14 | Borneol | 1157 | 1.44 | 0.88 | 0.73 | 0.58 | 0.59 | 0.62 | 0.67 | 0.65 | 0.64 | 0.85 | 0.73 | 0.59 | 0.59 | 0.63 | 0.67 | 0.66 | 0.61 |
15 | Terpinen-4-ol | 1169 | 1.83 | 0.82 | 0.68 | 0.53 | 0.54 | 0.58 | 0.63 | 0.61 | 0.59 | 0.81 | 0.67 | 0.54 | 0.54 | 0.59 | 0.63 | 0.62 | 0.58 |
16 | p-Cymen-8-ol | 1175 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | α-Terpineol | 1189 | 0.25 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
18 | Estragole | 1199 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | trans-Dihydro carvone | 1207 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Thymol, methyl ether | 1237 | 0.48 | 0.23 | 0.21 | 0.16 | 0.16 | 0.20 | 0.22 | 0.21 | - | 0.24 | 0.20 | 0.16 | 0.16 | 0.20 | 0.22 | 0.21 | - |
21 | Geranial | 1270 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | Carvone oxide | 1276 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | Thymol | 1292 | 55.77 | 60.59 | 63.44 | 67.2 | 67.67 | 67.44 | 65.08 | 64.45 | 65.16 | 61.23 | 63.62 | 67.33 | 67.59 | 67.56 | 64.84 | 64.52 | 65.57 |
24 | Carvacrol | 1301 | 4.97 | 4.66 | 4.15 | 3.51 | 3.57 | 3.78 | 3.62 | 3.56 | 3.83 | 4.58 | 4.04 | 3.55 | 3.56 | 3.78 | 3.58 | 3.62 | 3.74 |
25 | Thymol acetate | 1349 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Eugenol | 1351 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | Isoledene | 1365 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | α-Copaene | 1368 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Gurjunene | 1400 | 0.02 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | trans-Caryophyllene | 1410 | 2.48 | 1.85 | 1.60 | 1.38 | 1.40 | 1.40 | 1.27 | 1.27 | 1.39 | 1.78 | 1.59 | 1.39 | 1.39 | 1.39 | 1.27 | 1.28 | 1.35 |
31 | Aromandendrene | 1431 | 0.18 | 0.10 | 0.09 | - | - | - | - | - | - | 0.09 | 0.08 | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.15 | - | - | - | - | - | - | - | - | 0.09 | - | - | - | - | - | - | - |
33 | Alloaromadendrene | 1452 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | cis-Cadina-1(6),4-diene | 1462 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | γ-Muurolene | 1476 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | Viridiflorene | 1489 | 0.14 | 0.09 | - | - | - | - | - | - | - | 0.09 | - | - | - | - | - | - | - |
37 | α-Muurolene | 1494 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | γ-Cadinene | 1511 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
39 | trans-Calamenene | 1515 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
40 | δ-Cadinene | 1516 | 0.18 | 0.16 | 0.11 | - | - | - | - | - | - | 0.14 | 0.10 | - | - | - | - | - | - |
41 | Geranyl butanoate | 1555 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
42 | Spathulenol | 1571 | 0.15 | 0.09 | - | - | - | - | - | - | - | 0.08 | - | - | - | - | - | - | - |
43 | Caryophyllene oxide | 1576 | 0.43 | 0.27 | 0.22 | 0.18 | 0.18 | 0.18 | - | - | - | 0.27 | 0.21 | 0.17 | 0.17 | - | - | - | - |
44 | Geranyl 2-methyl butanoate | 1596 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
45 | Caryophylla-4(12),8(13)-dien-5α-ol | 1637 | 0.01 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 8.97 | 7.47 | 6.37 | 5.08 | 4.98 | 5.08 | 5.50 | 5.52 | 5.40 | 7.52 | 6.35 | 5.07 | 4.97 | 5.10 | 5.5 | 5.54 | 5.22 |
Oxygenated monoterpenes | 7.97 | 4.64 | 3.89 | 2.93 | 2.95 | 3.10 | 3.44 | 3.34 | 3.24 | 4.72 | 3.80 | 2.94 | 2.96 | 3.14 | 3.46 | 3.38 | 3.15 |
Phenolic monoterpenes | 78.27 | 85.01 | 87.6 | 90.43 | 90.49 | 90.24 | 89.79 | 89.87 | 89.97 | 85.07 | 87.74 | 90.42 | 90.5 | 90.37 | 89.77 | 89.79 | 90.28 |
Sesquiterpene hydrocarbons | 3.57 | 2.20 | 1.80 | 1.38 | 1.40 | 1.40 | 1.27 | 1.27 | 1.39 | 2.19 | 1.77 | 1.39 | 1.39 | 1.39 | 1.27 | 1.28 | 1.35 |
Oxygenated sesquiterpenes | 0.59 | 0.36 | 0.22 | 0.18 | 0.18 | 0.18 | - | - | - | 0.35 | 0.21 | 0.17 | 0.17 | - | - | - | - |
Total identified | 99.37 | 99.68 | 99.88 | 100 | 100 | 100 | 100 | 100 | 100 | 99.85 | 99.87 | 99.99 | 99.99 | 100 | 100 | 99.99 | 100 |
Table 10.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
Table 10.
Chemical composition (%) of Thymus vulgaris L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
| 4 °C Glass | 4 °C Metal | 4°C Ampoules | −20 °C |
---|
No. | Compounds | KI * | 1st ** | 30th | 60th | 90th | 120th | 150th | 180th | 180th | 180th | 180th |
---|
1 | α-Phellandrene | 1004 | 0.21 | 0.14 | 0.13 | 0.12 | - | - | - | - | 0.15 | 0.15 |
2 | δ-3-Carene | 1006 | 0.07 | 0.07 | 0.07 | - | - | - | - | - | - | - |
3 | α-Terpinene | 1012 | 2.03 | 1.64 | 1.56 | 1.04 | 0.88 | 1.20 | 0.83 | 1.07 | 1.31 | 1.34 |
4 | p-Cymene | 1022 | 16.79 | 17.15 | 16.71 | 18.99 | 18.43 | 22.45 | 18.26 | 20.89 | 21.8 | 22.98 |
5 | cis-β-Ocimene | 1028 | 0.01 | 0.67 | 0.65 | 0.4 | 0.32 | 0.40 | 0.32 | 0.37 | 0.46 | 0.48 |
6 | trans-β-Ocimene | 1047 | 0.04 | - | - | - | - | - | - | - | - | - |
7 | γ-Terpinene | 1054 | 6.32 | 5.72 | 5.79 | 4.80 | 4.22 | 4.86 | 4.16 | 4.71 | 5.46 | 5.09 |
8 | cis-Sabinene hydrate | 1069 | 0.29 | 0.18 | 0.17 | 0.11 | - | - | - | - | 0.13 | 0.14 |
9 | α-Terpinolene | 1087 | 0.29 | 0.22 | 0.20 | 0.11 | - | - | - | - | 0.17 | 0.17 |
10 | 2,4-Decadienal | 1091 | 0.02 | - | - | - | - | - | - | - | - | - |
11 | trans-Sabinene hydrate | 1094 | 0.04 | 0.07 | 0.07 | - | - | - | - | - | - | - |
12 | Linalool | 1101 | 3.72 | 3.21 | 3.19 | 2.33 | 1.90 | 2.15 | 1.90 | 2.08 | 2.42 | 2.44 |
13 | Camphor | 1134 | 0.09 | 0.04 | 0.08 | - | - | - | - | - | 0.11 | 0.11 |
14 | Borneol | 1157 | 1.44 | 1.12 | 1.10 | 0.74 | 0.61 | 0.66 | 0.64 | 0.67 | 0.80 | 0.81 |
15 | Terpinen-4-ol | 1169 | 1.83 | 1.03 | 1.04 | 0.68 | 0.57 | 0.61 | 0.58 | 0.60 | 0.71 | 0.73 |
16 | p-Cymen-8-ol | 1175 | 0.07 | - | - | - | - | - | - | - | - | - |
17 | α-Terpineol | 1189 | 0.25 | 0.25 | 0.23 | - | - | - | - | - | 0.10 | 0.09 |
18 | Estragole | 1199 | 0.06 | - | - | - | - | - | - | - | - | - |
19 | trans-Dihydro carvone | 1207 | 0.07 | - | - | - | - | - | - | - | - | - |
20 | Thymol, methyl ether | 1237 | 0.48 | 0.34 | 0.33 | 0.21 | 0.20 | 0.21 | 0.20 | 0.20 | 0.24 | 0.24 |
21 | Geranial | 1270 | 0.07 | 0.04 | - | - | - | - | - | - | - | - |
22 | Carvone oxide | 1276 | 0.04 | - | - | - | - | - | - | - | - | - |
23 | Thymol | 1292 | 55.77 | 59.13 | 60.15 | 64.07 | 67.57 | 62.69 | 67.75 | 64.39 | 60.22 | 59.80 |
24 | Carvacrol | 1301 | 4.97 | 5.32 | 5.11 | 4.10 | 3.73 | 3.50 | 3.92 | 3.70 | 4.32 | 3.81 |
25 | Thymol acetate | 1349 | 0.05 | - | - | - | - | - | - | - | - | - |
26 | Eugenol | 1351 | 0.08 | - | - | - | - | - | - | - | - | - |
27 | Isoledene | 1365 | 0.02 | - | - | - | - | - | - | - | - | - |
28 | α-Copaene | 1368 | 0.04 | - | - | - | - | - | - | - | - | - |
29 | α-Gurjunene | 1400 | 0.02 | - | - | - | - | - | - | - | - | - |
30 | trans-Caryophyllene | 1410 | 2.48 | 2.06 | 1.94 | 1.56 | 1.39 | 1.27 | 1.44 | 1.32 | 1.41 | 1.33 |
31 | Aromandendrene | 1431 | 0.18 | 0.12 | 0.11 | 0.08 | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.15 | 0.16 | 0.13 | - | - | - | - | - | - | - |
33 | Alloaromadendrene | 1452 | 0.07 | - | - | - | - | - | - | - | - | - |
34 | cis-Cadina-1(6),4-diene | 1462 | 0.04 | - | - | - | - | - | - | - | - | - |
35 | γ-Muurolene | 1476 | 0.06 | - | - | - | - | - | - | - | - | - |
36 | Viridiflorene | 1489 | 0.14 | 0.10 | 0.09 | - | - | - | - | - | - | - |
37 | α-Muurolene | 1494 | 0.05 | - | - | - | - | - | - | - | - | - |
38 | γ-Cadinene | 1511 | 0.09 | 0.06 | - | - | - | - | - | - | - | - |
39 | trans-Calamenene | 1515 | 0.05 | - | - | - | - | - | - | - | - | - |
40 | δ-Cadinene | 1516 | 0.18 | 0.19 | 0.21 | 0.15 | - | - | - | - | - | 0.08 |
41 | Geranyl butanoate | 1555 | 0.08 | - | - | - | - | - | - | - | - | - |
42 | Spathulenol | 1571 | 0.15 | 0.10 | 0.09 | - | - | - | - | - | - | - |
43 | Caryophyllene oxide | 1576 | 0.43 | 0.30 | 0.30 | 0.21 | 0.17 | - | - | - | 0.18 | 0.20 |
43 | Geranyl 2-methyl butanoate | 1596 | 0.03 | - | - | - | - | - | - | - | - | - |
45 | Caryophylla-4(12),8(13)-dien-5α-ol | 1637 | 0.01 | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 8.97 | 8.46 | 8.40 | 6.47 | 5.42 | 6.46 | 5.31 | 6.15 | 7.55 | 7.23 |
Oxygenated monoterpenes | 7.97 | 5.94 | 5.88 | 3.86 | 3.08 | 3.42 | 3.12 | 3.35 | 4.27 | 4.32 |
Phenolic monoterpenes | 78.27 | 81.94 | 82.3 | 87.37 | 89.93 | 88.85 | 90.13 | 89.18 | 86.58 | 86.83 |
Sesquiterpene hydrocarbons | 3.57 | 2.69 | 2.48 | 1.79 | 1.39 | 1.27 | 1.44 | 1.32 | 1.41 | 1.41 |
Oxygenated sesquiterpenes | 0.59 | 0.40 | 0.39 | 0.21 | 0.17 | - | - | - | 0.18 | 0.20 |
Total identified | 99.37 | 99.43 | 99.45 | 99.7 | 99.99 | 100 | 100 | 100 | 99.99 | 99.99 |
In the experiment where
Thymi aetheroleum was exposed to direct sunlight (
Table 7), a similar pattern of composition change was observed, with significant alterations occurring within the first 10 days and in the time interval of 80 to 100 days. An increase in the percentage of
cis-β-ocimene was also observed. After 6 months, the same substances as before (i.e., at room temperature without light exposure experiment) were detected, with a thymol percentage of 68.01%.
At high-temperature conditions of 35 °C and 45 °C (
Table 8 and
Table 9, respectively), encapsulating the essential oil in ampoules demonstrated enhanced stability compared to placing it in capped glass tubes. After 3 months in glass ampoules, only α-terpineol was no longer detectable at both temperatures, while the other substances were well preserved, resulting in a small increase in thymol percentage (60.72% at 35 °C and 60.36% at 45 °C vs. 55.77% in the original essential oil). In contrast, rapid deterioration occurred when the sample was placed in glass tubes at the same temperatures. Within the first 10 to 30 days, most components were no longer detectable. After 3 months, only the main compounds and
cis-β-ocimene remained in the essential oil, with thymol increasing to 65.16% at 35 °C and 65.57% at 45 °C.
When investigating the chemical load of
T. vulgaris essential oil under refrigeration conditions of 4 °C and −20 °C, it is notable that the preservation of its composition was similar to the above experiment (in high-temperature conditions) (
Table 10), without significant improvement compared to other conditions, as it would be expected. In glass tubes at 4 °C, the number of undetected components increased in each monthly measurement, and after 6 months, the compounds were reduced to the main ones along with
trans-β-ocimene and thymol methyl ether. The percentage of thymol in this measurement was 67.75%. The same substances were found in the sample stored in a metal container at the same temperature after 6 months. However, in the latter case, a smaller increase in the percentage of thymol (64.39%) was observed, while a significant increase in p-cymene (20.89% from 16.79% in the original sample) was noted. On the contrary, the sample stored in a glass ampoule exhibited better stability at the same temperature. Apart from the substances preserved in the previous two conditions, α-phellandrene,
cis-sabinene hydrate, α-terpinolene, camphor, α-terpineol, and caryophyllene oxide were also detected after 6 months. In this condition, the percentage of thymol increased to 60.22%, and the percentage of p-cymene also showed a significant increase (21.80%). Furthermore, increased retention of the substances was observed at −20 °C in glass tubes compared to the same container at 4 °C. After 6 months, more compounds remained in the sample at −20 °C, including α-phellandrene,
cis-sabinene hydrate, α-terpinolene, camphor, α-terpineol, caryophyllene oxide, and δ-cadinene. Moreover, the percentage of thymol was 59.80%, and the largest increase was observed in the percentage of p-cymene at 22.98%. It is worth mentioning that p-cymene is speculated to increase as a result of the transformation of α-phellandrene, α- and γ-terpinene, as well as in other cases of limonene [
16].
The essential oil of
T. vulgaris had a bright orange color. It is interesting that, after storage under direct sunlight, the intensity of the color decreased. No significant difference in color was observed during storage in the glass tubes at high temperatures of 35 °C and 45 °C (probably due to the initial color), while during storage in the ampoules at 45 °C after 3 months and at 35 °C and 45 °C after 6 months, the color turned to dark orange-red (
Figure 2).
3.1.3. Mentha spicata L.
In the essential oil of
M. spicata (spearmint), a total of 39 compounds were identified (
Table 11). The major constituents included carvone (73.69%), limonene (10.09%), terpinen-4-ol (ca. 2.28%), menthol (ca. 2.28%),
cis-dihydrocarvone (2.24%), caryophyllene (1.75%), and p-menthone (0.96%). The composition of the essential oil indicates a high content of oxygenated monoterpenes (84.92%), followed by monoterpene hydrocarbons (10.09%), sesquiterpene hydrocarbons (3.74%), and traces of oxygenated sesquiterpenes (0.6%), and phenolic monoterpenes (0.27%). These findings are in agreement with reports of the percentage composition of this particular essential oil in the literature [
17].
Under room temperature conditions and in the absence of light (in glass tubes) (
Table 11), several components initially present in low proportions no longer appeared in the mixture after Day 10. It is worth noting that during the degradation of spearmint essential oil, certain compounds that are not originally present in the chemical composition are produced, namely neo-menthol, menthol, α-terpineol, and carveol. Specifically, α-terpineol results from sabinene hydrate with C-C bond cleavage [
16], neo-menthol and menthol are produced from limonene or in other cases pulegone [
18], and carveol is probably derived from limonene [
19]. The chemical accumulation remains during the period of 10 to 30 days, while in the measurement after 40 days, isopulegol, carveol, and
cis-β-farnesene are no longer detected. Subsequently, between 70 and 120 days, additional substances disappear from the sample, including
trans-dihydrocarvone, neo-menthol, α-, iso-menthol, p-cymene, and caryophyllene oxide. Finally, in the last four measurements (Days 140–170), nine components are detected in the sample, namely limonene, p-menthone, menthol, terpinen-4-ol,
cis-dihydrocarvone, carvone, dihydro carveol acetate, β-bourbonene, and caryophyllene, with carvone being the predominant compound, constituting 88.85% of the mixture.
Table 11.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
Table 11.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | p-Cymene | 1017 | 0.27 | 0.45 | 0.23 | 0.25 | 0.22 | 0.22 | 0.23 | 0.23 | 0.17 | 0.12 | 0.11 | - | - | - | - | - | - | - |
2 | Limonene | 1022 | 10.09 | 9.86 | 10.29 | 10.38 | 10.18 | 10.45 | 10.28 | 10.03 | 8.79 | 8.37 | 7.53 | 6.95 | 7.02 | 8.84 | 8.56 | 7.63 | 7.61 | 7.06 |
3 | cis-Sabinene hydrate | 1069 | 0.11 | 0.28 | 0.08 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
4 | trans-p-Mentha-2,8-dien-1-ol | 1115 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | cis-Limonene oxide | 1126 | 0.09 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
6 | trans-Limonene oxide | 1130 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | Isopulegol | 1138 | 0.15 | 0.11 | 0.08 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
8 | p-Menthone | 1144 | 0.96 | 0.88 | 0.75 | 0.8 | 0.67 | 0.64 | 0.65 | 0.64 | 0.46 | 0.38 | 0.34 | 0.31 | 0.31 | 0.44 | 0.40 | 0.32 | 0.35 | 0.34 |
9 | Isomenthone | 1154 | 0.69 | 0.39 | 0.32 | 0.34 | 0.27 | 0.25 | 0.26 | 0.26 | 0.19 | 0.06 | - | - | - | - | - | - | - | - |
10 | Neomenthol | 1156 | - | 0.24 | 0.19 | 0.21 | 0.18 | 0.17 | 0.16 | 0.17 | - | - | - | - | - | - | - | - | - | - |
11 | Menthol | 1165 | - | 3.01 | 2.55 | 2.72 | 2.32 | 2.26 | 2.14 | 2.22 | 1.60 | 1.29 | 1.21 | 1.01 | 0.98 | 1.37 | 1.26 | 1.06 | 1.05 | 0.98 |
12 | Terpinen-4-ol + Menthol | 1169 | 4.56 | 1.24 | 1.10 | 1.18 | 1.03 | 0.99 | 0.94 | 0.96 | 0.70 | 0.60 | 0.55 | 0.48 | 0.47 | 0.61 | 0.57 | 0.51 | 0.51 | 0.49 |
13 | α-Terpineol | 1183 | - | 0.63 | 0.46 | 0.52 | 0.47 | 0.40 | 0.43 | 0.41 | 0.24 | 0.18 | 0.23 | - | - | - | - | - | - | - |
14 | cis-Dihydrocarvone | 1189 | 2.24 | 1.88 | 1.72 | 1.82 | 1.51 | 1.34 | 1.41 | 1.34 | 0.93 | 0.75 | 0.78 | 0.70 | 0.69 | 1.11 | 0.79 | 0.70 | 0.86 | 0.73 |
15 | trans-Dihydrocarvone | 1195 | 0.84 | 0.21 | 0.21 | 0.16 | 0.17 | 0.16 | 0.16 | - | - | - | - | - | - | - | - | - | - | - |
16 | Carveol | 1213 | - | 0.12 | 0.16 | 0.16 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Carvone | 1233 | 73.69 | 75.71 | 77.1 | 76.44 | 78.89 | 79.63 | 78.83 | 80.09 | 84.200 | 86.21 | 87.19 | 88.62 | 88.89 | 86.05 | 86.96 | 88.32 | 88.15 | 88.85 |
18 | Isopiperitone | 1255 | 0.37 | 0.39 | 0.38 | 0.39 | 0.43 | 0.35 | 0.35 | 0.34 | 0.21 | 0.17 | 0.18 | 0.18 | 0.17 | 0.17 | - | - | - | - |
19 | Carvenone | 1256 | tr | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Menthyl acetate | 1290 | 0.25 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | Dihydro carveol acetate | 1303 | 0.61 | 0.51 | 0.5 | 0.50 | 0.44 | 0.41 | 0.40 | 0.40 | 0.34 | 0.28 | 0.28 | 0.28 | 0.28 | 0.26 | 0.27 | 0.26 | 0.26 | 0.29 |
22 | Neoisoverbanol acetate | 1330 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Carveyl acetate | 1336 | 0.16 | 0.13 | 0.11 | 0.10 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
24 | α-Copaene | 1367 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | β-Bourbonene | 1379 | 0.83 | 0.71 | 0.71 | 0.70 | 0.67 | 0.60 | 0.58 | 0.6 | 0.49 | 0.41 | 0.42 | 0.41 | 0.40 | 0.37 | 0.38 | 0.40 | 0.40 | 0.45 |
26 | β-Elemene | 1384 | 0.16 | 0.13 | 0.12 | 0.12 | 0.11 | 0.10 | 0.10 | 0.11 | - | - | - | - | - | - | - | - | - | - |
27 | trans-Jasmone | 1387 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | cis-Caryophyllene | 1397 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | trans-Caryophyllene | 1410 | 1.75 | 1.48 | 1.50 | 1.51 | 1.40 | 1.27 | 1.24 | 1.26 | 1.09 | 0.90 | 0.91 | 0.8 | 0.79 | 0.77 | 0.80 | 0.80 | 0.81 | 0.81 |
30 | β-Copaene | 1423 | 0.17 | 0.14 | 0.15 | 0.15 | 0.13 | 0.13 | 0.12 | - | - | - | - | - | - | - | - | - | - | - |
31 | Aromadendrene | 1432 | 0.10 | 0.08 | 0.07 | 0.10 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.19 | 0.15 | 0.15 | 0.15 | 0.15 | 0.12 | 0.12 | 0.13 | 0.11 | - | - | - | - | - | - | - | - | - |
33 | cis-β-Farnesene | 1452 | 0.18 | 0.13 | 0.10 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | Germacrene D | 1477 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | α-Amorphene | 1482 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | α-Muurolene | 1494 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
37 | δ-Cadinene | 1515 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | Caryophyllene oxide | 1576 | 0.55 | 0.45 | 0.44 | 0.44 | 0.37 | 0.33 | 0.37 | 0.39 | 0.36 | 0.28 | 0.27 | 0.25 | - | - | - | - | - | - |
39 | Viridiflorol | 1584 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 10.09 | 9.86 | 10.29 | 10.38 | 10.18 | 10.45 | 10.28 | 10.03 | 8.79 | 8.37 | 7.53 | 6.95 | 7.02 | 8.84 | 8.56 | 7.63 | 7.61 | 7.06 |
Oxygenated monoterpenes | 84.92 | 85.8 | 85.71 | 85.51 | 86.38 | 86.6 | 85.73 | 86.83 | 88.87 | 89.92 | 90.76 | 91.58 | 91.79 | 90.01 | 90.25 | 91.17 | 91.18 | 91.68 |
Phenolic monoterpenes | 0.27 | 0.45 | 0.23 | 0.25 | 0.22 | 0.22 | 0.23 | 0.23 | 0.17 | 0.12 | 0.11 | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.74 | 2.82 | 2.80 | 2.82 | 2.00 | 2.22 | 2.16 | 2.10 | 1.69 | 1.31 | 1.33 | 1.21 | 1.19 | 1.14 | 1.18 | 1.20 | 1.21 | 1.26 |
Oxygenated sesquiterpenes | 0.60 | 0.45 | 0.44 | 0.44 | 0.37 | 0.33 | 0.37 | 0.39 | 0.36 | 0.28 | 0.27 | 0.25 | - | - | - | - | - | - |
Total identified | 99.62 | 99.38 | 99.47 | 99.4 | 99.75 | 99.82 | 98.77 | 99.58 | 99.88 | 100 | 100 | 99.99 | 100 | 99.99 | 99.99 | 100 | 100 | 100 |
Table 12.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
Table 12.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | p-Cymene | 1017 | 0.27 | 0.40 | 0.26 | 0.27 | 0.22 | 0.25 | 0.23 | 0.23 | 0.23 | 0.12 | 0.11 | - | - | - | - | - | - | - |
2 | Limonene | 1022 | 10.09 | 10.72 | 10.69 | 10.37 | 10.21 | 9.37 | 10.31 | 10.19 | 8.24 | 7.8 | 7.55 | 6.98 | 7.18 | 8.26 | 8.35 | 7.73 | 7.67 | 7.29 |
3 | cis-Sabinene hydrate | 1069 | 0.11 | 0.13 | 0.09 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
4 | trans-p-Mentha-2,8-dien-1-ol | 1115 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | cis-Limonene oxide | 1126 | 0.09 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
6 | trans-Limonene oxide | 1130 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | Isopulegol | 1138 | 0.15 | 0.09 | 0.09 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
8 | p-Menthone | 1144 | 0.96 | 0.74 | 0.79 | 0.81 | 0.60 | 0.60 | 0.65 | 0.67 | 0.45 | 0.35 | 0.33 | 0.31 | 0.36 | 0.44 | 0.42 | 0.33 | 0.35 | 0.33 |
9 | Isomenthone | 1154 | 0.69 | 0.33 | 0.34 | 0.34 | 0.22 | 0.24 | 0.26 | 0.27 | - | - | - | - | - | - | - | - | - | - |
10 | Neomenthol | 1156 | - | 0.19 | 0.20 | 0.20 | 0.16 | 0.16 | 0.16 | 0.18 | 0.05 | 0.05 | - | - | - | - | - | - | - | - |
11 | Menthol | 1165 | - | 2.55 | 2.65 | 2.73 | 2.17 | 2.09 | 2.16 | 2.33 | 1.59 | 1.21 | 1.18 | 1.03 | 1.06 | 1.40 | 1.33 | 1.08 | 1.08 | 1.02 |
12 | Terpinen-4-ol + Menthol | 1169 | 4.56 | 1.08 | 1.12 | 1.17 | 0.94 | 0.91 | 0.93 | 1.00 | 0.69 | 0.57 | 0.55 | 0.49 | 0.50 | 0.61 | 0.59 | 0.51 | 0.51 | 0.48 |
13 | α-Terpineol | 1183 | - | 0.53 | 0.55 | 0.49 | 0.40 | 0.35 | 0.45 | 0.46 | 0.32 | 0.18 | 0.22 | - | - | - | - | - | - | - |
14 | cis-Dihydrocarvone | 1189 | 2.24 | 1.64 | 1.74 | 1.80 | 1.27 | 1.19 | 1.40 | 1.52 | 1.01 | 0.73 | 0.75 | 0.70 | 0.73 | 0.81 | 0.86 | 0.76 | 0.69 | 0.71 |
15 | trans-Dihydrocarvone | 1195 | 0.84 | 0.18 | 0.19 | 0.22 | 0.22 | 0.16 | 0.16 | 0.18 | - | - | - | - | - | - | - | - | - | - |
16 | Carveol | 1213 | - | 0.17 | 0.17 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Carvone | 1233 | 73.69 | 76.85 | 76.32 | 76.48 | 80.08 | 80.83 | 79.94 | 79.04 | 84.81 | 86.98 | 87.33 | 88.73 | 88.4 | 86.71 | 87.11 | 88.26 | 88.37 | 88.74 |
18 | Isopiperitone | 1255 | 0.37 | 0.36 | 0.39 | 0.40 | 0.55 | 0.30 | 0.33 | 0.34 | 0.23 | 0.17 | 0.17 | - | - | - | - | - | - | - |
19 | Carvenone | 1256 | TR | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Menthyl acetate | 1290 | 0.25 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | Dihydro carveol acetate | 1303 | 0.61 | 0.47 | 0.49 | 0.50 | 0.38 | 0.43 | 0.40 | 0.43 | 0.32 | 0.28 | 0.28 | 0.27 | 0.28 | 0.27 | 0.27 | 0.27 | 0.27 | 0.30 |
22 | Neoisoverbanol acetate | 1330 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Carveyl acetate | 1336 | 0.16 | 0.11 | 0.11 | 0.10 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
24 | α-Copaene | 1367 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | β-Bourbonene | 1379 | 0.83 | 0.67 | 0.70 | 0.71 | 0.58 | 0.65 | 0.59 | 0.65 | 0.48 | 0.44 | 0.44 | 0.42 | 0.42 | 0.38 | 0.40 | 0.41 | 0.41 | 0.44 |
26 | β-Elemene | 1384 | 0.16 | 0.12 | 0.12 | 0.13 | 0.11 | 0.11 | 0.1 | 0.11 | - | - | - | - | - | - | - | - | - | - |
27 | trans-Jasmone | 1387 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | cis-Caryophyllene | 1397 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | trans-Caryophyllene | 1410 | 1.75 | 1.37 | 1.40 | 1.38 | 1.18 | 1.19 | 1.14 | 1.24 | 0.95 | 0.82 | 0.79 | 0.77 | 0.75 | 0.65 | 0.67 | 0.65 | 0.65 | 0.69 |
30 | β-Copaene | 1423 | 0.17 | 0.13 | 0.14 | 0.15 | 0.13 | 0.13 | 0.12 | 0.13 | - | - | - | - | - | - | - | - | - | - |
31 | Aromadendrene | 1432 | 0.10 | 0.07 | 0.09 | 0.11 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.19 | 0.11 | 0.14 | 0.14 | 0.12 | 0.12 | 0.12 | 0.13 | - | - | - | - | - | - | - | - | - | - |
33 | cis-β-Farnesene | 1452 | 0.18 | 0.10 | 0.10 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | Germacrene D | 1477 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | α-Amorphene | 1482 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | α-Muurolene | 1494 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
37 | δ-Cadinene | 1515 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | Caryophyllene oxide | 1576 | 0.55 | 0.43 | 0.45 | 0.52 | 0.30 | 0.49 | 0.40 | 0.46 | 0.33 | 0.31 | 0.30 | 0.30 | 0.31 | 0.29 | - | - | - | - |
39 | Viridiflorol | 1584 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 10.09 | 10.72 | 10.69 | 10.37 | 10.21 | 9.37 | 10.31 | 10.19 | 8.24 | 7.80 | 7.55 | 6.98 | 7.18 | 8.26 | 8.35 | 7.73 | 7.67 | 7.29 |
Oxygenated monoterpenes | 84.92 | 85.50 | 85.24 | 85.58 | 86.99 | 87.26 | 86.84 | 86.42 | 89.47 | 90.17 | 90.81 | 91.53 | 91.33 | 90.24 | 90.58 | 91.21 | 91.27 | 91.58 |
Phenolic monoterpenes | 0.27 | 0.40 | 0.26 | 0.27 | 0.22 | 0.25 | 0.23 | 0.23 | 0.23 | 0.12 | 0.11 | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.74 | 2.57 | 2.69 | 2.69 | 2.12 | 2.20 | 2.07 | 2.26 | 1.43 | 1.26 | 1.23 | 1.19 | 1.17 | 1.03 | 1.07 | 1.06 | 1.06 | 1.13 |
Oxygenated sesquiterpenes | 0.60 | 0.43 | 0.45 | 0.52 | 0.30 | 0.49 | 0.40 | 0.46 | 0.33 | 0.31 | 0.30 | 0.30 | 0.31 | 0.29 | - | - | - | - |
Total identified | 99.62 | 99.62 | 99.33 | 99.43 | 99.84 | 99.57 | 99.85 | 99.56 | 99.7 | 99.66 | 100 | 100 | 99.99 | 99.82 | 100 | 100 | 100 | 100 |
Table 13.
Chemical composition (%) of Mentha spicata L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
Table 13.
Chemical composition (%) of Mentha spicata L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | p-Cymene | 1017 | 0.27 | 0.41 | 0.27 | 0.27 | 0.21 | 0.26 | 0.23 | 0.24 | 0.22 | 0.42 | 0.23 | 0.26 | 0.21 | 0.25 | 0.24 | 0.23 | 0.20 |
2 | Limonene | 1022 | 10.09 | 10.48 | 11.09 | 10.96 | 9.89 | 9.33 | 10.22 | 10.14 | 8.12 | 10.05 | 9.84 | 10.6 | 10.46 | 8.53 | 10.09 | 10.19 | 8.43 |
3 | cis-Sabinene hydrate | 1069 | 0.11 | 0.23 | 0.08 | 0.10 | 0.10 | 0.10 | 0.08 | - | - | 0.22 | 0.09 | 0.09 | 0.09 | 0.09 | 0.07 | - | - |
4 | trans-p-Mentha-2,8-dien-1-ol | 1115 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | cis-Limonene oxide | 1126 | 0.09 | - | - | - | - | - | - | - | - | 0.09 | 0.09 | - | - | - | - | - | - |
6 | trans-Limonene oxide | 1130 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | Isopulegol | 1138 | 0.15 | 0.10 | 0.10 | 0.10 | - | - | - | - | - | 0.10 | 0.09 | 0.09 | - | - | - | - | - |
8 | p-Menthone | 1144 | 0.96 | 0.85 | 0.76 | 0.83 | 0.67 | 0.77 | 0.69 | 0.65 | 0.43 | 0.82 | 0.73 | 0.78 | 0.64 | 0.72 | 0.69 | 0.64 | 0.43 |
9 | Isomenthone | 1154 | 0.69 | 0.37 | 0.31 | 0.35 | 0.26 | 0.32 | 0.27 | 0.25 | - | 0.35 | 0.29 | 0.33 | 0.24 | 0.29 | 0.27 | 0.25 | - |
10 | Neomenthol | 1156 | - | 0.22 | 0.19 | 0.22 | 0.17 | 0.19 | 0.17 | 0.17 | - | 0.21 | 0.18 | 0.20 | 0.19 | 0.19 | 0.17 | 0.16 | - |
11 | Menthol | 1165 | - | 2.83 | 2.54 | 2.73 | 2.35 | 2.62 | 2.25 | 2.23 | 1.54 | 2.82 | 2.55 | 2.63 | 2.28 | 2.42 | 2.29 | 2.22 | 1.56 |
12 | Terpinen-4-ol + Menthol | 1169 | 4.56 | 1.19 | 1.08 | 1.16 | 1.02 | 1.03 | 0.99 | 0.98 | 0.67 | 1.16 | 1.02 | 1.12 | 0.99 | 0.99 | 1.01 | 0.96 | 0.69 |
13 | α-Terpineol | 1183 | - | 0.57 | 0.54 | 0.57 | 0.47 | 0.54 | 0.43 | 0.45 | 0.33 | 0.57 | 0.50 | 0.56 | 0.42 | 0.52 | 0.45 | 0.38 | 0.31 |
14 | cis-Dihydrocarvone | 1189 | 2.24 | 1.84 | 1.66 | 1.78 | 1.49 | 1.68 | 1.51 | 1.46 | 1.00 | 1.81 | 1.65 | 1.71 | 1.35 | 1.60 | 1.54 | 1.30 | 0.99 |
15 | trans-Dihydrocarvone | 1195 | 0.84 | 0.21 | 0.19 | 0.21 | 0.16 | 0.17 | 0.18 | 0.16 | - | 0.20 | 0.18 | 0.19 | 0.16 | 0.16 | 0.18 | - | - |
16 | Carveol | 1213 | - | 0.18 | 0.18 | 0.17 | 0.17 | 0.20 | 0.15 | - | - | 0.18 | 0.18 | 0.17 | 0.17 | 0.19 | 0.12 | - | - |
17 | Carvone | 1233 | 73.69 | 75.71 | 76.89 | 75.83 | 79.43 | 78.95 | 78.96 | 79.53 | 85.36 | 76.26 | 77.89 | 76.54 | 79.27 | 79.79 | 79.07 | 80.06 | 84.98 |
18 | Isopiperitone | 1255 | 0.37 | 0.39 | 0.43 | 0.43 | 0.46 | 0.31 | 0.33 | 0.35 | 0.27 | 0.40 | 0.31 | 0.40 | 0.40 | 0.30 | 0.32 | 0.29 | 0.22 |
19 | Carvenone | 1256 | tr | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Menthyl acetate | 1290 | 0.25 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | Dihydro carveol acetate | 1303 | 0.61 | 0.51 | 0.45 | 0.49 | 0.44 | 0.46 | 0.42 | 0.42 | 0.30 | 0.51 | 0.47 | 0.48 | 0.40 | 0.45 | 0.42 | 0.41 | 0.32 |
22 | Neoisoverbanol acetate | 1330 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Carveyl acetate | 1336 | 0.16 | 0.12 | 0.12 | 0.12 | 0.10 | 0.10 | - | - | - | 0.12 | 0.10 | 0.11 | - | - | - | - | - |
24 | α-Copaene | 1367 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | β-Bourbonene | 1379 | 0.83 | 0.70 | 0.64 | 0.69 | 0.63 | 0.63 | 0.63 | 0.60 | 0.47 | 0.73 | 0.69 | 0.69 | 0.59 | 0.64 | 0.64 | 0.59 | 0.47 |
26 | β-Elemene | 1384 | 0.16 | 0.13 | 0.11 | 0.12 | 0.11 | 0.11 | 0.11 | 0.11 | - | 0.13 | 0.12 | 0.12 | 0.11 | 0.11 | 0.11 | 0.10 | - |
27 | trans-Jasmone | 1387 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | cis-Caryophyllene | 1397 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | trans-Caryophyllene | 1410 | 1.75 | 1.50 | 1.15 | 1.43 | 1.10 | 0.61 | 1.33 | 1.29 | 1.04 | 1.51 | 0.75 | 1.41 | 1.30 | 0.86 | 1.32 | 1.27 | 1.04 |
30 | β-Copaene | 1423 | 0.17 | 0.15 | 0.13 | 0.14 | 0.13 | 0.11 | 0.13 | 0.12 | - | 0.15 | 0.13 | 0.14 | 0.13 | 0.13 | 0.13 | 0.12 | - |
31 | Aromadendrene | 1432 | 0.10 | 0.08 | 0.09 | 0.09 | - | - | - | - | - | 0.09 | 0.07 | 0.07 | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.19 | 0.15 | 0.12 | 0.15 | 0.13 | 0.10 | 0.13 | 0.13 | - | 0.15 | 0.11 | 0.14 | 0.12 | 0.12 | 0.13 | 0.12 | - |
33 | cis-β-Farnesene | 1452 | 0.18 | 0.13 | 0.12 | 0.12 | - | - | - | - | - | 0.12 | 0.10 | 0.10 | - | - | - | - | - |
34 | Germacrene D | 1477 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | α-Amorphene | 1482 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | α-Muurolene | 1494 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
37 | δ-Cadinene | 1515 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | Caryophyllene oxide | 1576 | 0.55 | 0.45 | 0.44 | 0.44 | 0.34 | 0.99 | 0.39 | 0.38 | 0.25 | 0.48 | 0.96 | 0.43 | 0.32 | 0.80 | 0.40 | 0.38 | 0.29 |
39 | Viridiflorol | 1584 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 10.09 | 10.48 | 11.09 | 10.96 | 9.89 | 9.33 | 10.22 | 10.14 | 8.12 | 10.05 | 9.84 | 10.6 | 10.46 | 8.53 | 10.09 | 10.19 | 8.43 |
Oxygenated monoterpenes | 84.92 | 85.32 | 85.52 | 85.09 | 87.29 | 87.44 | 86.43 | 86.65 | 89.90 | 85.82 | 86.32 | 85.4 | 86.6 | 87.71 | 86.6 | 86.67 | 89.5 |
Phenolic monoterpenes | 0.27 | 0.41 | 0.27 | 0.27 | 0.21 | 0.26 | 0.23 | 0.24 | 0.22 | 0.42 | 0.23 | 0.26 | 0.21 | 0.25 | 0.24 | 0.23 | 0.20 |
Sesquiterpene hydrocarbons | 3.74 | 2.84 | 2.36 | 2.74 | 2.10 | 1.56 | 2.33 | 2.25 | 1.51 | 2.88 | 1.97 | 2.67 | 2.25 | 1.86 | 2.33 | 2.20 | 1.51 |
Oxygenated sesquiterpenes | 0.60 | 0.45 | 0.44 | 0.44 | 0.34 | 0.99 | 0.39 | 0.38 | 0.25 | 0.48 | 0.96 | 0.43 | 0.32 | 0.80 | 0.40 | 0.38 | 0.29 |
Total identified | 99.62 | 99.5 | 99.68 | 99.5 | 99.83 | 99.58 | 99.6 | 99.66 | 100 | 99.65 | 99.32 | 99.36 | 99.84 | 99.15 | 99.66 | 99.67 | 99.93 |
Table 14.
Chemical composition (%) of Mentha spicata L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
Table 14.
Chemical composition (%) of Mentha spicata L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | p-Cymene | 1017 | 0.27 | 0.25 | 0.17 | 0.11 | - | - | - | - | - | 0.21 | 0.15 | 0.11 | - | - | - | - | - |
2 | Limonene | 1022 | 10.09 | 10.68 | 8.72 | 7.55 | 6.94 | 7.14 | 8.18 | 8.24 | 7.65 | 9.52 | 9.06 | 7.46 | 6.94 | 7.13 | 8.17 | 8.23 | 7.61 |
3 | cis-Sabinene hydrate | 1069 | 0.11 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
4 | trans-p-Mentha-2,8-dien-1-ol | 1115 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | cis-Limonene oxide | 1126 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
6 | trans-Limonene oxide | 1130 | 0.08 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
7 | Isopulegol | 1138 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
8 | p-Menthone | 1144 | 0.96 | 0.69 | 0.44 | 0.33 | 0.32 | 0.33 | 0.44 | 0.42 | 0.35 | 0.56 | 0.47 | 0.32 | 0.32 | 0.33 | 0.45 | 0.41 | 0.34 |
9 | Isomenthone | 1154 | 0.69 | 0.29 | 0.06 | - | - | - | - | - | - | 0.23 | 0.19 | - | - | - | - | - | - |
10 | Neomenthol | 1156 | - | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
11 | Menthol | 1165 | - | 2.40 | 1.56 | 1.18 | 1.03 | 1.07 | 1.41 | 1.32 | 1.07 | 1.91 | 1.63 | 1.17 | 1.03 | 1.07 | 1.42 | 1.29 | 1.07 |
12 | Terpinen-4-ol + Menthol | 1169 | 4.56 | 0.96 | 0.68 | 0.54 | 0.49 | 0.49 | 0.61 | 0.59 | 0.51 | 0.81 | 0.73 | 0.54 | 0.49 | 0.50 | 0.62 | 0.57 | 0.50 |
13 | α-Terpineol | 1183 | - | 0.41 | 0.30 | - | - | - | - | - | - | 0.38 | 0.25 | - | - | - | - | - | - |
14 | cis-Dihydrocarvone | 1189 | 2.24 | 1.35 | 0.99 | 0.76 | 0.70 | 0.75 | 0.82 | 0.85 | 0.88 | 1.20 | 0.93 | 0.76 | 0.69 | 0.73 | 0.87 | 0.80 | 0.85 |
15 | trans-Dihydrocarvone | 1195 | 0.84 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Carvone | 1233 | 73.69 | 79.77 | 84.69 | 87.49 | 88.51 | 88.21 | 86.69 | 87.17 | 88.13 | 82.34 | 83.84 | 87.62 | 88.7 | 88.42 | 86.80 | 86.99 | 87.91 |
18 | Isopiperitone | 1255 | 0.37 | 0.25 | 0.24 | 0.17 | 0.16 | 0.16 | 0.17 | - | - | 0.26 | 0.22 | 0.18 | - | - | - | - | - |
19 | Carvenone | 1256 | tr | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
20 | Menthyl acetate | 1290 | 0.25 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | Dihydro carveol acetate | 1303 | 0.61 | 0.38 | 0.32 | 0.27 | 0.27 | 0.28 | 0.27 | 0.28 | 0.27 | 0.36 | 0.35 | 0.28 | 0.27 | 0.28 | 0.27 | 0.27 | 0.27 |
22 | Neoisoverbanol acetate | 1330 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | trans-Carveyl acetate | 1336 | 0.16 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
24 | α-Copaene | 1367 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | β-Bourbonene | 1379 | 0.83 | 0.53 | 0.47 | 0.43 | 0.43 | 0.41 | 0.38 | 0.39 | 0.40 | 0.52 | 0.52 | 0.42 | 0.41 | 0.42 | 0.38 | 0.39 | 0.39 |
26 | β-Elemene | 1384 | 0.16 | 0.10 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | trans-Jasmone | 1387 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | cis-Caryophyllene | 1397 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | trans-Caryophyllene | 1410 | 1.75 | 1.09 | 1.02 | 0.86 | 0.84 | 0.83 | 0.72 | 0.74 | 0.74 | 1.09 | 1.07 | 0.83 | 0.8 | 0.77 | 0.68 | 0.69 | 0.70 |
30 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
31 | Aromadendrene | 1432 | 0.1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.19 | 0.11 | - | - | - | - | - | - | - | 0.11 | 0.11 | - | - | - | - | - | - |
33 | cis-β-Farnesene | 1452 | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
34 | Germacrene D | 1477 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
35 | α-Amorphene | 1482 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
36 | α-Muurolene | 1494 | 0.03 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
37 | δ-Cadinene | 1515 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
38 | Caryophyllene oxide | 1576 | 0.55 | 0.38 | 0.33 | 0.30 | 0.31 | 0.33 | 0.31 | - | - | 0.38 | 0.36 | 0.32 | 0.34 | 0.35 | 0.34 | 0.35 | 0.36 |
39 | Viridiflorol | 1584 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 10.09 | 10.68 | 8.72 | 7.55 | 6.94 | 7.14 | 8.18 | 8.24 | 7.65 | 9.52 | 9.06 | 7.46 | 6.94 | 7.13 | 8.17 | 8.23 | 7.61 |
Oxygenated monoterpenes | 84.92 | 86.68 | 89.28 | 90.74 | 91.48 | 91.29 | 90.41 | 90.63 | 91.21 | 88.05 | 88.61 | 90.87 | 91.5 | 91.33 | 90.43 | 90.33 | 90.94 |
Phenolic monoterpenes | 0.27 | 0.25 | 0.17 | 0.11 | - | - | - | - | - | 0.21 | 0.15 | 0.11 | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.74 | 1.83 | 1.49 | 1.29 | 1.27 | 1.24 | 1.10 | 1.13 | 1.14 | 1.72 | 1.70 | 1.25 | 1.21 | 1.19 | 1.06 | 1.08 | 1.09 |
Oxygenated sesquiterpenes | 0.60 | 0.38 | 0.33 | 0.30 | 0.31 | 0.33 | 0.31 | - | - | 0.38 | 0.36 | 0.32 | 0.34 | 0.35 | 0.34 | 0.35 | 0.36 |
Total identified | 99.62 | 99.82 | 99.99 | 99.99 | 100 | 100 | 100 | 100 | 100 | 99.88 | 99.88 | 99.9 | 99.99 | 100 | 100 | 99.99 | 100 |
Table 15.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers, and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
Table 15.
Chemical composition (%) of Mentha spicata L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers, and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
| 4 °C Glass | 4 °C Metal | 4 °C Ampoules | −20 °C |
---|
No. | Compound | KI * | 1st ** | 30th | 60th | 90th | 120th | 150th | 180th | 180th | 180th | 180th |
---|
1 | p-Cymene | 1017 | 0.27 | 0.25 | 0.23 | - | - | - | - | 0.17 | 0.16 | - |
2 | Limonene | 1022 | 10.09 | 10.08 | 9.69 | 6.84 | 7.22 | 7.30 | 7.30 | 10.18 | 9.34 | 7.41 |
3 | cis-Sabinene hydrate | 1069 | 0.11 | 0.09 | - | - | - | - | - | - | - | - |
4 | trans-p-Mentha-2,8-dien-1-ol | 1115 | 0.06 | - | - | - | - | - | - | - | - | - |
5 | cis-Limonene oxide | 1126 | 0.09 | - | - | - | - | - | - | - | - | - |
6 | trans-Limonene oxide | 1130 | 0.08 | - | - | - | - | - | - | - | - | - |
7 | Isopulegol | 1138 | 0.15 | 0.08 | - | - | - | - | - | - | - | - |
8 | p-Menthone | 1144 | 0.96 | 0.82 | 0.64 | 0.30 | 0.36 | 0.33 | 0.33 | 0.53 | 0.52 | 0.33 |
9 | Isomenthone | 1154 | 0.69 | 0.35 | 0.26 | - | - | - | - | 0.12 | 0.13 | - |
10 | Neomenthol | 1156 | - | 0.21 | 0.17 | - | - | - | - | - | - | - |
11 | Menthol | 1165 | - | 2.76 | 2.24 | 0.99 | 1.06 | 0.98 | 0.97 | 1.51 | 1.52 | 1.01 |
12 | Terpinen-4-ol + Menthol | 1169 | 4.56 | 1.21 | 0.97 | 0.48 | 0.50 | 0.50 | 0.49 | 0.84 | 0.80 | 0.49 |
13 | α-Terpineol | 1183 | - | 0.50 | 0.42 | - | - | - | - | 0.31 | 0.27 | - |
14 | cis-Dihydrocarvone | 1189 | 2.24 | 1.89 | 1.35 | 0.66 | 0.75 | 0.70 | 0.67 | 1.34 | 0.94 | 0.67 |
15 | trans-Dihydrocarvone | 1195 | 0.84 | 0.84 | - | - | - | - | - | - | - | - |
16 | Carveol | 1213 | - | 0.18 | - | - | - | - | - | - | - | - |
17 | Carvone | 1235 | 73.69 | 76.09 | 80.72 | 88.93 | 88.47 | 88.59 | 88.62 | 82.81 | 84.16 | 88.35 |
18 | Isopiperitone | 1255 | 0.37 | 0.36 | 0.29 | 0.16 | - | - | - | 0.18 | 0.20 | - |
19 | Carvenone | 1256 | tr | - | - | - | - | - | - | - | - | - |
20 | Menthyl acetate | 1290 | 0.25 | - | - | - | - | - | - | 0.11 | - | - |
21 | Dihydro carveol acetate | 1303 | 0.61 | 0.51 | 0.40 | 0.26 | 0.28 | 0.28 | 0.29 | 0.31 | 0.31 | 0.29 |
22 | Neoisoverbanol acetate | 1330 | 0.06 | - | - | - | - | - | - | - | - | - |
23 | trans-Carveyl acetate | 1336 | 0.16 | 0.11 | - | - | - | - | - | - | - | - |
24 | α-Copaene | 1367 | 0.06 | - | - | - | - | - | - | - | - | - |
25 | β-Bourbonene | 1379 | 0.83 | 0.73 | 0.59 | 0.41 | 0.41 | 0.40 | 0.43 | 0.42 | 0.44 | 0.44 |
26 | β-Elemene | 1384 | 0.16 | 0.14 | 0.11 | - | - | - | - | - | - | - |
27 | trans-Jasmone | 1387 | 0.06 | - | - | - | - | - | - | - | - | - |
28 | cis-Caryophyllene | 1397 | 0.03 | - | - | - | - | - | - | - | - | - |
29 | trans-Caryophyllene | 1410 | 1.75 | 1.56 | 1.31 | 0.97 | 0.95 | 0.92 | 0.90 | 0.89 | 0.95 | 1.01 |
30 | β-Copaene | 1423 | 0.17 | 0.15 | - | - | - | - | - | - | - | - |
31 | Aromadendrene | 1432 | 0.10 | 0.20 | - | - | - | - | - | - | - | - |
32 | α-Humulene | 1445 | 0.19 | 0.16 | 0.13 | - | - | - | - | - | - | - |
33 | cis-β-Farnesene | 1452 | 0.18 | 0.10 | - | - | - | - | - | - | - | - |
34 | Germacrene D | 1477 | 0.05 | - | - | - | - | - | - | - | - | - |
35 | α-Amorphene | 1482 | 0.07 | - | - | - | - | - | - | - | - | - |
36 | α-Muurolene | 1494 | 0.03 | - | - | - | - | - | - | - | - | - |
37 | δ-Cadinene | 1515 | 0.06 | - | - | - | - | - | - | - | - | - |
38 | Caryophyllene oxide | 1576 | 0.55 | 0.43 | 0.33 | - | - | - | - | 0.28 | 0.26 | - |
39 | Viridiflorol | 1584 | 0.05 | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 10.09 | 10.08 | 9.69 | 6.84 | 7.22 | 7.30 | 7.30 | 10.18 | 9.34 | 7.41 |
Oxygenated monoterpenes | 84.92 | 86.00 | 87.46 | 91.78 | 91.42 | 91.38 | 91.37 | 88.06 | 88.85 | 91.14 |
Phenolic monoterpenes | 0.27 | 0.25 | 0.23 | - | - | - | - | 0.17 | 0.16 | - |
Sesquiterpene hydrocarbons | 3.74 | 3.04 | 2.14 | 1.38 | 1.36 | 1.32 | 1.33 | 1.31 | 1.39 | 1.45 |
Oxygenated sesquiterpenes | 0.60 | 0.43 | 0.33 | - | - | - | - | 0.28 | 0.26 | - |
Total identified | 99.62 | 99.8 | 99.85 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Deterioration of the essential oil follows a similar pattern during storage at room temperature and in direct sunlight (
Table 12). Components with low concentration become undetectable after 10 days, and the gradual loss of substances eventually leads to the presence of only the nine above-mentioned compounds. The formation of neo-menthol, menthol, α-terpineol, and carveol in this condition further supports their status as degradation products of the essential oil [
16]. The percentage of carvone increases to 88.74% after 170 days, compared to 73.69% in the initial sample.
The enhanced stability achieved through encapsulating the essential oil In glass ampoules is evident once again in the experiments conducted at 35 °C and 45 °C (
Table 13). Despite the higher temperature, which typically leads to reduced stability, a greater number of substances can be found in the final measurement (Day 80). In addition to the previously mentioned compounds, p-cymene, α-terpineol, isopiperitone, and caryophyllene oxide are preserved. Nevertheless, the sample still undergoes changes with the loss of substances and the formation of degradation products, similar to the previous conditions. The percentage of carvone increases to 85.36% at 35 °C and 84.98% at 45 °C, compared to 73.69% in the original sample after a 3-month period. Under the same temperature conditions, but in a different container (clear glass with a cap;
Table 14), the composition shows a different pattern. The essential oils rapidly lose compounds with low concentrations, and gradually, the remaining substances diminish until, after 3 months, only the nine aforementioned components remain. The observed degradation products in these conditions are neo-menthol, menthol, and α-terpineol (carveol is not formed). The percentage of carvone increases significantly to 88.13% and 87.91% at 35 °C and 45 °C, respectively.
Finally, in cooling conditions (
Table 15), the effect of the container on the preservation of the essential oil components becomes strongly evident. At 4 °C in clear glass tubes, the composition of the final sample after 6 months remains similar to that of the previous conditions, while the formation of all four degradation products is observed. The percentage of carvone significantly increases to 88.62%. In contrast, when stored in a metal container at the same temperature for 6 months, additional compounds such as p-cymene, iso-menthone, α-terpineol, isopiperitone, menthyl acetate, and caryophyllene oxide are preserved in the mixture, and the percentage of carvone increases to only 82.81%. Similarly, the same additional ingredients, except for menthyl acetate, are retained in the glass ampoules, and the concentration of carvone increases slightly more (84.16%), but not as much as in the glass tubes (88.62%). Moreover, the final composition of the sample that remains for 6 months in glass test tubes at −20 °C does not differ significantly from that at 4 °C in the same container, from which we conclude that at low temperatures, the effect of the container is significant.
After storage in various conditions, the color of
M. spicata essential oil changed from pale yellow to a more intense yellow, being more distinct at high temperatures (35 °C and 45 °C) and especially in glass tubes with caps. The color intensity was maintained for a longer period in the ampoules at the same temperatures, but after 6 months, the color turned dark yellow. Similarly to the previous ones, the sample color stored under sunlight faded to pale yellow (
Figure 2).
3.1.4. Mentha × piperita L.
In the
M. ×
piperita (peppermint) essential oil, a total of 33 compounds were identified (
Table 16) with the main ones being isomenthol (36.59%), menthone (21.70%), iso-menthone (10.17%), menthyl acetate (6.56%), neomenthol (6.42%), limonene (4.95%), isopulegol (2.00%), α-terpineol (1.92%),
trans-caryophyllene (1.35%), isopiperitone (1.31%), neoisomenthol (1.15%), and pulegone (1.10%). This indicates that the essential oil is particularly abundant in oxygenated monoterpenes (82.94%), while monoterpene hydrocarbons (4.95%), sesquiterpene hydrocarbons (3.66%), and other minor chemical groups such as phenolic monoterpenes (0.15%), and oxygenated sesquiterpenes (0.12%). Moreover, other compounds (7.02%) from different categories are found in smaller quantities. This observed composition is consistent with other reports of essential oil analysis of the same species [
20].
Most of the substances present in the mixture at low concentrations (<0.20%) could no longer be detected after storage for just 10 days at room temperature in the absence of light (in glass tubes) (
Table 16). In continuation, the chemical composition remained relatively stable until Day 30. Of note, γ-terpinene, not present in the initial analysis of peppermint essential oil, became detectable within measurements of 10 to 30 days. This suggests that this substance is a degradation product of a main compound of the sample, probably limonene [
21]. In the measurement after 40 days, the absence of 3-octanol and p-cymene was observed. By Day 60, α-guaiene could no longer be detected. During the period between 80 and 140 days, the composition gradually changed, leading to a reduction in the number of detectable substances. Eventually, in the last four measurements, only six compounds remained detectable: limonene, menthone, isomenthone, neomenthol, iso-menthol, and menthyl acetate. The percentage of isomenthol, therefore, increased from 36.59% in the initial sample to 52.33% in the final measurement after 6 months.
Table 16.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
Table 16.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage in clear glass tubes sealed with cap at room temperature (23 °C) under darkness.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | 3-Octanol | 991 | 0.42 | 0.28 | 0.28 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
2 | p-Cymene | 1019 | 0.15 | 0.25 | 0.22 | 0.10 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | Limonene | 1022 | 4.95 | 2.43 | 4.85 | 4.48 | 4.41 | 4.35 | 4.35 | 3.94 | 3.37 | 3.31 | 3.53 | 3.65 | 4.04 | 4.37 | 4.82 | 4.39 | 4.30 | 4.02 |
4 | γ-Terpinene | 1054 | - | 0.17 | 0.16 | 0.13 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | Linalool | 1097 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
6 | Isopulegol | 1141 | 2.00 | 1.48 | 1.76 | 1.60 | 1.44 | 1.43 | 1.42 | 1.34 | 1.11 | 0.99 | 1.02 | - | - | - | - | - | - | - |
7 | Menthone | 1150 | 21.70 | 22.4 | 22.95 | 22.57 | 22.78 | 22.77 | 22.94 | 22.35 | 21.9 | 22.04 | 22.08 | 23.6 | 23.64 | 25.32 | 25.12 | 24.08 | 24.01 | 22.71 |
8 | Isomenthone | 1159 | 10.17 | 9.74 | 10.16 | 10.08 | 9.75 | 9.71 | 9.66 | 9.42 | 8.68 | 8.47 | 8.76 | 9.13 | 9.13 | 9.14 | 9.67 | 9.33 | 9.30 | 8.82 |
9 | Neomenthol | 1163 | 6.42 | 6.89 | 6.98 | 6.88 | 6.73 | 6.74 | 6.58 | 6.60 | 6.02 | 5.58 | 5.86 | 5.80 | 5.80 | 5.55 | 6.00 | 5.91 | 5.90 | 5.56 |
10 | Isomenthol | 1178 | 36.59 | 44.18 | 40.11 | 40.75 | 42.54 | 42.67 | 43.77 | 44.61 | 48.01 | 49.21 | 49.61 | 50.45 | 49.49 | 48.45 | 48.64 | 50.46 | 50.74 | 52.33 |
11 | Neoisomenthol | 1182 | 1.15 | 0.99 | 0.99 | 1.01 | 0.96 | 0.95 | 0.91 | 0.91 | 0.85 | 0.78 | 0.84 | - | - | - | - | - | - | - |
12 | α-Terpineol | 1189 | 1.92 | 1.57 | 1.60 | 1.63 | 1.45 | 1.45 | 1.41 | 1.42 | 1.35 | 1.31 | 1.35 | 1.35 | 1.58 | 1.33 | - | - | - | - |
13 | Dihydro carveol | 1192 | 0.21 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
14 | cis-Piperitol | 1198 | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Pulegone | 1231 | 1.10 | 0.82 | 0.85 | 0.91 | 0.74 | 0.75 | 0.68 | 0.73 | 0.68 | 0.70 | - | - | - | - | - | - | - | - |
16 | Carvone | 1236 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Isopiperitone | 1245 | 1.31 | 0.94 | 0.98 | 1.10 | 0.8 | 0.78 | 0.72 | 0.78 | 0.70 | 0.74 | - | - | - | - | - | - | - | - |
18 | Dihydroedulan II | 1281 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | Menthyl acetate | 1292 | 6.56 | 5.86 | 6.00 | 6.35 | 6.27 | 6.31 | 5.78 | 5.98 | 5.79 | 5.73 | 5.85 | 6.02 | 6.32 | 5.84 | 5.75 | 5.83 | 5.75 | 6.56 |
20 | δ-Elemene | 1331 | 0.36 | 0.27 | 0.29 | 0.30 | 0.28 | 0.28 | 0.27 | 0.28 | - | - | - | - | - | - | - | - | - | - |
21 | Longicyclene | 1362 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | α-Ylangene | 1364 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | α-Copaene | 1369 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
24 | β-Bourbonene | 1379 | 0.66 | 0.49 | 0.52 | 0.55 | 0.52 | 0.51 | 0.49 | 0.52 | 0.47 | - | - | - | - | - | - | - | - | - |
25 | β-Elemene | 1386 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Longifolene | 1396 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | trans-Caryophyllene | 1410 | 1.35 | 1.04 | 1.08 | 1.15 | 1.11 | 1.10 | 1.02 | 1.12 | 1.07 | 1.13 | 1.09 | - | - | - | - | - | - | - |
28 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | β-Gurjunene | 1434 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | α-Guaiene | 1442 | 0.31 | 0.20 | 0.22 | 0.24 | 0.21 | 0.20 | - | - | - | - | - | - | - | - | - | - | - | - |
31 | γ-Muurolene | 1477 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | Germacrene D | 1484 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
33 | Caryophyllene oxide | 1576 | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 4.95 | 2.60 | 5.01 | 4.61 | 4.41 | 4.35 | 4.35 | 3.94 | 3.37 | 3.31 | 3.53 | 3.65 | 4.04 | 4.37 | 4.82 | 4.39 | 4.30 | 4.02 |
Oxygenated monoterpenes | 82.94 | 89.01 | 86.38 | 86.53 | 87.19 | 87.25 | 88.09 | 88.16 | 89.30 | 89.82 | 89.52 | 90.33 | 89.64 | 89.79 | 89.43 | 89.78 | 89.95 | 89.42 |
Phenolic monoterpenes | 0.15 | 0.25 | 0.22 | 0.10 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.66 | 2.00 | 2.11 | 2.24 | 2.12 | 2.09 | 1.78 | 1.92 | 1.54 | 1.13 | 1.09 | - | - | - | - | - | - | - |
Oxygenated sesquiterpenes | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | -- |
Others | 7.02 | 6.14 | 6.28 | 6.52 | 6.27 | 6.31 | 5.78 | 5.98 | 5.79 | 5.73 | 5.85 | 6.02 | 6.32 | 5.84 | 5.75 | 5.83 | 5.75 | 6.56 |
Total identified | 98.84 | 100 | 100 | 100 | 99.99 | 100 | 100 | 100 | 100 | 99.99 | 99.99 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Table 17.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
Table 17.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage in clear glass tubes sealed with cap under direct sunlight exposure.
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 90th ** | 100th ** | 110th ** | 120th ** | 130th ** | 140th ** | 150th ** | 160th ** | 170th ** |
---|
1 | 3-Octanol | 991 | 0.42 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
2 | p-Cymene | 1019 | 0.15 | 0.21 | 0.24 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | Limonene | 1022 | 4.95 | 4.07 | 4.29 | 4.36 | 4.01 | 3.94 | 4.09 | 4.02 | 3.72 | 3.41 | 3.41 | 3.62 | 4.10 | 4.00 | 4.41 | 4.23 | 4.36 | 4.12 |
4 | Linalool | 1097 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | Isopulegol | 1141 | 2.00 | 1.40 | 1.49 | 1.47 | 1.43 | 1.65 | 1.43 | 1.38 | 1.14 | 1.03 | 1.01 | - | - | - | - | - | - | - |
6 | Menthone | 1150 | 21.70 | 22.79 | 22.83 | 22.83 | 22.14 | 22.57 | 22.73 | 22.57 | 22.58 | 22.25 | 22.33 | 23.24 | 23.51 | 25.08 | 25.51 | 24.06 | 24.04 | 23.50 |
7 | lsomenthone | 1159 | 10.17 | 9.63 | 9.87 | 10.00 | 9.49 | 9.50 | 9.58 | 9.46 | 8.90 | 8.72 | 8.93 | 9.10 | 9.10 | 9.25 | 9.59 | 9.44 | 9.53 | 9.13 |
8 | Neomenthol | 1163 | 6.42 | 6.62 | 6.81 | 6.87 | 6.88 | 6.94 | 6.64 | 6.65 | 6.04 | 5.82 | 5.92 | 5.72 | 5.72 | 5.65 | 5.85 | 6.03 | 6.07 | 5.84 |
9 | Isomenthol | 1178 | 36.59 | 43.39 | 42.28 | 42.14 | 43.45 | 43.68 | 43.65 | 44.44 | 47.31 | 49.84 | 50.28 | 50.13 | 48.75 | 49.01 | 47.53 | 50.41 | 50.38 | 51.81 |
10 | Neoisomenthol | 1182 | 1.15 | 0.93 | 0.98 | 0.98 | 0.97 | 0.96 | 0.92 | 0.92 | 0.83 | 0.82 | 0.80 | 0.80 | 0.84 | 0.55 | - | - | - | - |
11 | α-Terpineol | 1189 | 1.92 | 1.48 | 1.56 | 1.56 | 1.51 | 1.52 | 1.48 | 1.42 | 1.30 | 1.36 | 1.28 | 1.28 | 1.56 | 1.36 | 1.46 | - | - | - |
12 | Dihydro carveol | 1192 | 0.21 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
13 | cis-Piperitol | 1198 | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
14 | Pulegone | 1231 | 1.10 | 0.78 | 0.82 | 0.78 | 0.76 | 0.74 | 0.73 | 0.68 | 0.58 | - | - | - | - | - | - | - | - | - |
15 | Carvone | 1236 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | Isopiperitone | 1245 | 1.31 | 0.88 | 0.81 | 0.81 | 0.74 | 0.77 | 0.75 | 0.65 | 0.58 | - | - | - | - | - | - | - | - | - |
17 | Dihydroedulan II | 1281 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
18 | Menthyl acetate | 1292 | 6.56 | 5.85 | 6.00 | 6.19 | 6.52 | 5.79 | 6.01 | 6.07 | 5.70 | 5.85 | 6.04 | 6.11 | 6.42 | 5.10 | 5.65 | 5.83 | 5.62 | 5.60 |
19 | δ-Elemene | 1331 | 0.36 | 0.27 | 0.28 | 0.28 | 0.29 | 0.28 | 0.29 | 0.28 | - | - | - | - | - | - | - | - | - | - |
20 | Longicyclene | 1362 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | α-Ylangene | 1364 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | α-Copaene | 1369 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | β-Bourbonene | 1379 | 0.66 | 0.49 | 0.51 | 0.51 | 0.54 | 0.51 | 0.52 | 0.52 | 0.46 | - | - | - | - | - | - | - | - | - |
24 | β-Elemene | 1386 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | Longifolene | 1396 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | trans-Caryophyllene | 1411 | 1.35 | 1.00 | 1.02 | 1.02 | 1.06 | 0.94 | 0.97 | 0.94 | 0.86 | 0.90 | - | - | - | - | - | - | - | - |
27 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | β-Gurjunene | 1434 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Guaiene | 1442 | 0.31 | 0.20 | 0.20 | 0.20 | 0.21 | 0.21 | 0.21 | - | - | - | - | - | - | - | - | - | - | - |
30 | γ-Muurolene | 1476 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
31 | Germacrene D | 1484 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | Caryophyllene oxide | 1576 | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 4.95 | 4.07 | 4.29 | 4.36 | 4.01 | 3.94 | 4.09 | 4.02 | 3.72 | 3.41 | 3.41 | 3.62 | 4.10 | 4.00 | 4.41 | 4.23 | 4.36 | 4.12 |
Oxygenated monoterpenes | 82.94 | 87.9 | 87.45 | 87.44 | 87.37 | 88.33 | 87.91 | 88.17 | 89.26 | 89.84 | 90.55 | 90.27 | 89.48 | 90.9 | 89.94 | 89.94 | 90.02 | 90.28 |
Phenolic monoterpenes | 0.15 | 0.21 | 0.24 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.66 | 1.96 | 2.01 | 2.01 | 2.01 | 1.94 | 1.99 | 1.74 | 1.32 | 0.90 | - | - | - | - | - | - | - | - |
Oxygenated sesquiterpenes | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Others | 7.02 | 5.85 | 6.00 | 6.19 | 6.52 | 5.79 | 6.01 | 6.07 | 5.70 | 5.85 | 6.04 | 6.11 | 6.42 | 5.10 | 5.65 | 5.83 | 5.62 | 5.60 |
Total identified | 98.84 | 99.99 | 99.99 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Table 18.
Chemical composition (%) of Mentha × piperita L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
Table 18.
Chemical composition (%) of Mentha × piperita L. essential oil during 3 months of storage in sealed glass ampoules at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | 3-Octanol | 991 | 0.42 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
2 | p-Cymene | 1019 | 0.15 | 0.51 | 0.14 | - | - | - | - | - | - | 0.39 | 0.13 | - | - | - | - | - | - |
3 | Limonene | 1022 | 4.95 | 4.16 | 4.61 | 4.35 | 4.41 | 4.38 | 4.52 | 4.16 | 4.20 | 3.91 | 4.51 | 4.28 | 4.13 | 4.12 | 4.36 | 4.27 | 3.49 |
4 | γ-Terpinene | 1054 | - | 0.26 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | Linalool | 1097 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
6 | Isopulegol | 1141 | 2.00 | 1.49 | 1.56 | 1.67 | 1.41 | 1.44 | 1.49 | 1.40 | 1.13 | 1.43 | 1.54 | 1.51 | 1.43 | 1.52 | 1.47 | 1.40 | 1.15 |
7 | Menthone | 1150 | 21.7 | 22.15 | 22.83 | 23.11 | 22.76 | 22.64 | 23.08 | 22.67 | 22.89 | 22.45 | 22.69 | 22.37 | 22.22 | 22.00 | 23.00 | 22.92 | 22.29 |
8 | lsomenthone | 1159 | 10.17 | 9.48 | 9.96 | 9.88 | 9.70 | 9.67 | 9.71 | 9.50 | 9.22 | 9.58 | 9.95 | 9.59 | 9.49 | 9.41 | 9.71 | 9.63 | 8.78 |
9 | Neomenthol | 1163 | 6.42 | 6.78 | 6.95 | 6.83 | 6.76 | 6.71 | 6.64 | 6.61 | 5.96 | 6.79 | 6.94 | 6.74 | 6.85 | 6.85 | 6.66 | 6.52 | 6.11 |
10 | Isomenthol | 1178 | 36.59 | 43.09 | 41.67 | 42.03 | 43.00 | 43.61 | 44.04 | 43.9 | 45.95 | 43.71 | 41.86 | 43.47 | 43.33 | 44.28 | 43.33 | 43.5 | 47.10 |
11 | Neoisomenthol | 1182 | 1.15 | 0.97 | 0.99 | 0.96 | 0.94 | 0.95 | 0.47 | 0.90 | 0.82 | 0.95 | 0.99 | 0.96 | 0.94 | 0.95 | 0.91 | 0.89 | 0.82 |
12 | α-Terpineol | 1189 | 1.92 | 1.54 | 1.55 | 1.54 | 1.42 | 1.46 | 0.93 | 1.43 | 1.30 | 1.50 | 1.57 | 1.51 | 1.47 | 1.52 | 1.43 | 1.42 | 1.36 |
13 | Dihydro carveol | 1192 | 0.21 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
14 | cis-Piperitol | 1198 | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
15 | Pulegone | 1231 | 1.10 | 0.76 | 0.80 | 0.82 | 0.71 | 0.74 | 0.70 | 0.74 | 0.65 | 0.74 | 0.81 | 0.78 | 0.77 | 0.77 | 0.73 | 0.80 | 0.76 |
16 | Carvone | 1236 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
17 | Isopiperitone | 1245 | 1.31 | 0.84 | 0.88 | 0.92 | 0.72 | 0.81 | 0.75 | 0.76 | 0.63 | 0.80 | 0.87 | 0.86 | 0.78 | 0.82 | 0.74 | 0.78 | 0.73 |
18 | Dihydroedulan II | 1281 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
19 | Menthyl acetate | 1292 | 6.56 | 5.92 | 6.03 | 5.88 | 6.29 | 5.79 | 5.85 | 6.02 | 5.68 | 5.81 | 6.15 | 5.92 | 6.45 | 5.96 | 5.84 | 6.01 | 5.85 |
20 | δ-Elemene | 1331 | 0.36 | 0.28 | 0.28 | 0.29 | 0.28 | 0.27 | 0.28 | 0.29 | - | 0.27 | 0.28 | 0.28 | 0.29 | 0.29 | 0.28 | 0.28 | - |
21 | Longicyclene | 1362 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | α-Ylangene | 1364 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | α-Copaene | 1369 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
24 | β-Bourbonene | 1379 | 0.66 | 0.51 | 0.51 | 0.51 | 0.51 | 0.49 | 0.50 | 0.52 | 0.51 | 0.48 | 0.44 | 0.50 | 0.52 | 0.45 | 0.50 | 0.51 | 0.48 |
25 | β-Elemene | 1386 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | Longifolene | 1396 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
27 | trans-Caryophyllene | 1411 | 1.35 | 1.05 | 1.03 | 1.00 | 1.08 | 1.03 | 1.04 | 1.10 | 1.02 | 0.96 | 1.06 | 1.03 | 1.11 | 1.06 | 1.04 | 1.07 | 1.07 |
28 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | β-Gurjunene | 1434 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | α-Guaiene | 1442 | 0.31 | 0.21 | 0.21 | 0.21 | - | - | - | - | - | 0.21 | 0.21 | 0.20 | 0.21 | - | - | - | - |
31 | γ-Muurolene | 1476 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | Germacrene D | 1484 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
33 | Caryophyllene oxide | 1576 | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 4.95 | 4.42 | 4.61 | 4.35 | 4.41 | 4.38 | 4.52 | 4.16 | 4.20 | 3.91 | 4.51 | 4.28 | 4.13 | 4.12 | 4.36 | 4.27 | 3.49 |
Oxygenated monoterpenes | 82.94 | 87.1 | 87.19 | 87.76 | 87.42 | 88.03 | 87.81 | 87.91 | 88.55 | 87.95 | 87.22 | 87.79 | 87.28 | 88.12 | 87.98 | 87.86 | 89.1 |
Phenolic monoterpenes | 0.15 | 0.51 | 0.14 | - | - | - | - | - | - | 0.39 | 0.13 | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.66 | 2.05 | 2.03 | 2.01 | 1.87 | 1.79 | 1.82 | 1.91 | 1.53 | 1.92 | 1.99 | 2.01 | 2.13 | 1.80 | 1.82 | 1.86 | 1.55 |
Oxygenated sesquiterpenes | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Others | 7.02 | 5.92 | 6.03 | 5.88 | 6.29 | 5.79 | 5.85 | 6.02 | 5.68 | 5.81 | 6.15 | 5.92 | 6.45 | 5.96 | 5.84 | 6.01 | 5.85 |
Total identified | 98.84 | 100 | 100 | 100 | 99.99 | 99.99 | 100 | 100 | 99.96 | 99.98 | 100 | 100 | 99.99 | 100 | 100 | 100 | 99.99 |
Table 19.
Chemical composition (%) of Mentha × piperita L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
Table 19.
Chemical composition (%) of Mentha × piperita L. essential oil during 3 months of storage in clear glass tubes sealed with cap at a temperature of 35 °C and 45 °C.
| 35 °C | 45 °C |
---|
No. | Compound | KI * | 1st ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** | 10th ** | 20th ** | 30th ** | 40th ** | 50th ** | 60th ** | 70th ** | 80th ** |
---|
1 | 3-Octanol | 991 | 0.42 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
2 | p-Cymene | 1019 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
3 | Limonene | 1022 | 4.95 | 4.33 | 3.88 | 3.58 | 3.60 | 4.07 | 4.08 | 4.49 | 4.28 | 3.65 | 3.62 | 3.52 | 3.53 | 3.52 | 3.65 | 3.65 | 4.29 |
4 | Linalool | 1097 | 0.14 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
5 | Isopulegol | 1141 | 2.00 | 1.32 | 1.15 | 1.01 | - | - | - | - | - | 1.20 | 1.11 | 1.02 | 1.02 | 1.02 | 1.45 | 1.20 | - |
6 | Menthone | 1150 | 21.70 | 23.83 | 23.12 | 22.28 | 22.97 | 22.93 | 25.07 | 25.11 | 24.03 | 22.55 | 22.59 | 22.6 | 22.22 | 22.03 | 22.04 | 22.55 | 23.99 |
7 | lsomenthone | 1159 | 10.17 | 9.22 | 9.10 | 8.90 | 9.01 | 8.84 | 9.23 | 9.50 | 9.45 | 8.85 | 8.91 | 9.02 | 9.12 | 9.17 | 9.26 | 8.85 | 9.49 |
8 | Neomenthol | 1163 | 6.42 | 6.25 | 5.97 | 5.94 | 5.88 | 5.57 | 5.64 | 5.80 | 5.94 | 6.07 | 5.98 | 5.96 | 6.00 | 5.90 | 5.63 | 6.07 | 6.01 |
9 | Isomenthol | 1178 | 36.59 | 44.63 | 45.94 | 48.18 | 48.04 | 47.76 | 45.31 | 46.95 | 50.48 | 46.42 | 46.66 | 48.62 | 49.02 | 49.72 | 49.42 | 49.05 | 50.38 |
10 | Neoisomenthol | 1182 | 1.15 | 0.86 | 0.83 | 0.82 | 0.81 | 0.81 | 0.75 | - | - | 0.82 | 0.81 | 0.78 | 0.78 | 0.78 | 0.74 | 0.82 | - |
11 | α-Terpineol | 1189 | 1.92 | 1.33 | 1.32 | 1.32 | 1.54 | 1.54 | 1.40 | 1.46 | - | 1.36 | 1.33 | 1.33 | 1.33 | 1.31 | 1.31 | 1.36 | - |
12 | Dihydro carveol | 1192 | 0.21 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
13 | cis-Piperitol | 1198 | 0.18 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
14 | Pulegone | 1231 | 1.1 | 0.64 | 0.70 | - | - | - | - | - | - | 0.71 | 0.69 | 0.69 | 0.69 | 0.69 | 0.66 | 0.71 | - |
15 | Carvone | 1236 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
16 | Isopiperitone | 1245 | 1.31 | 0.67 | 0.73 | 1.04 | 1.09 | 1.09 | 1.04 | 1.08 | - | 0.76 | 0.76 | 0.76 | 0.74 | 0.69 | 0.66 | 0.59 | - |
17 | Dihydroedulan II | 1281 | 0.04 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
18 | Menthyl acetate | 1292 | 6.56 | 5.47 | 5.74 | 5.90 | 6.03 | 6.24 | 5.41 | 5.61 | 5.81 | 5.81 | 5.80 | 5.70 | 5.55 | 5.17 | 5.16 | 5.15 | 5.84 |
19 | δ-Elemene | 1331 | 0.36 | - | - | - | - | - | - | - | - | 0.28 | 0.28 | - | - | - | - | - | - |
20 | Longicyclene | 1362 | 0.09 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
21 | α-Ylangene | 1364 | 0.06 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
22 | α-Copaene | 1369 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
23 | β-Bourbonene | 1379 | 0.66 | 0.48 | 0.48 | - | - | - | - | - | - | 0.49 | 0.49 | - | - | - | - | - | - |
24 | β-Elemene | 1386 | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
25 | Longifolene | 1396 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
26 | trans-Caryophyllene | 1411 | 1.35 | 0.95 | 1.04 | 1.03 | 1.03 | 1.14 | - | - | - | 1.02 | 0.97 | - | - | - | - | - | - |
27 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
28 | β-Gurjunene | 1434 | 0.07 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
29 | α-Guaiene | 1442 | 0.31 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
30 | γ-Muurolene | 1476 | 0.05 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
31 | Germacrene D | 1484 | 0.17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
32 | Caryophyllene oxide | 1576 | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 4.95 | 4.33 | 3.88 | 3.58 | 3.60 | 4.07 | 4.08 | 4.49 | 4.28 | 3.65 | 3.62 | 3.52 | 3.53 | 3.52 | 3.65 | 3.65 | 4.29 |
Oxygenated monoterpenes | 82.94 | 88.75 | 88.86 | 89.49 | 89.34 | 88.54 | 88.44 | 89.90 | 89.90 | 88.74 | 88.84 | 90.78 | 90.92 | 91.31 | 91.17 | 91.2 | 89.87 |
Phenolic monoterpenes | 0.15 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.66 | 1.43 | 1.52 | 1.03 | 1.03 | 1.14 | - | - | - | 1.79 | 1.74 | - | - | - | - | - | - |
Oxygenated sesquiterpenes | 0.12 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Others | 7.02 | 5.47 | 5.74 | 5.90 | 6.03 | 6.24 | 5.41 | 5.61 | 5.81 | 5.81 | 5.80 | 5.70 | 5.55 | 5.17 | 5.16 | 5.15 | 5.84 |
Total identified | 98.84 | 99.98 | 100 | 100 | 100 | 99.99 | 97.93 | 100 | 99.99 | 99.99 | 100 | 100 | 100 | 100 | 99.98 | 100 | 100 |
Table 20.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
Table 20.
Chemical composition (%) of Mentha × piperita L. essential oil during 6 months of storage at 4 °C (in clear glass tubes sealed with cap, in metal containers and in sealed glass ampoules) and at −20 °C (in clear glass tubes sealed with cap).
| 4 °C Glass Tubes | 4 °C Metal | 4 °C Ampoules | −20 °C |
---|
No. | Compound | KI * | 1st ** | 30th | 60th | 90th | 120th | 150th | 180th | 180th | 180th | 180th |
---|
1 | 3-Octanol | 991 | 0.42 | - | - | - | - | - | - | - | - | - |
2 | p-Cymene | 1019 | 0.15 | - | - | - | - | - | - | - | - | - |
3 | Limonene | 1022 | 4.95 | 4.36 | 4.07 | 3.50 | 4.10 | 4.20 | 4.04 | 4.56 | 4.37 | 4.03 |
4 | Linalool | 1097 | 0.14 | - | - | - | - | - | - | - | - | - |
5 | Isopulegol | 1141 | 2.00 | 1.48 | 1.40 | - | - | - | - | 1.47 | 1.56 | - |
6 | Menthone | 1150 | 21.7 | 22.72 | 22.34 | 22.29 | 22.92 | 22.85 | 22.34 | 24.56 | 24.61 | 23.11 |
7 | lsomenthone | 1159 | 10.17 | 9.92 | 9.46 | 9.44 | 8.92 | 8.90 | 8.76 | 9.11 | 9.29 | 8.73 |
8 | Neomenthol | 1163 | 6.42 | 6.88 | 6.72 | 6.23 | 5.66 | 5.60 | 5.57 | 6.01 | 6.06 | 5.58 |
9 | Isomenthol | 1178 | 36.59 | 42.10 | 44.39 | 49.01 | 48.79 | 49.84 | 50.71 | 43.26 | 43.41 | 49.01 |
10 | Neoisomenthol | 1182 | 1.15 | 0.98 | 0.94 | 0.91 | 0.85 | - | - | 0.75 | 0.79 | - |
11 | α-Terpineol | 1189 | 1.92 | 1.56 | 1.43 | 1.50 | 1.59 | 1.56 | 1.56 | 1.32 | 1.38 | 1.60 |
12 | Dihydro carveol | 1192 | 0.21 | - | - | - | - | - | - | - | - | - |
13 | cis-Piperitol | 1198 | 0.18 | - | - | - | - | - | - | - | - | - |
14 | Pulegone | 1231 | 1.10 | 0.80 | 0.67 | - | - | - | - | 0.93 | 0.94 | - |
15 | Carvone | 1236 | 0.05 | - | - | - | - | - | - | - | - | - |
16 | Isopiperitone | 1245 | 1.31 | 0.89 | 0.73 | - | - | - | - | 1.07 | 1.02 | |
17 | Dihydroedulan II | 1281 | 0.04 | - | - | - | - | - | - | - | - | - |
18 | Menthyl acetate | 1292 | 6.56 | 6.19 | 5.96 | 5.92 | 5.90 | 5.80 | 5.77 | 5.10 | 5.03 | 6.54 |
19 | δ-Elemene | 1331 | 0.36 | 0.28 | 0.28 | - | - | - | - | - | - | - |
20 | Longicyclene | 1362 | 0.09 | - | - | - | - | - | - | - | - | - |
21 | α-Ylangene | 1364 | 0.06 | - | - | - | - | - | - | - | - | - |
22 | α-Copaene | 1369 | 0.15 | - | - | - | - | - | - | - | - | - |
23 | β-Bourbonene | 1379 | 0.66 | 0.52 | 0.50 | - | - | - | - | 0.50 | 0.48 | - |
24 | β-Elemene | 1386 | 0.15 | - | - | - | - | - | - | - | - | - |
25 | Longifolene | 1396 | 0.07 | - | - | - | - | - | - | - | - | - |
26 | trans-Caryophyllene | 1411 | 1.35 | 1.09 | 1.10 | 1.20 | 1.27 | 1.25 | 1.25 | 1.07 | 1.05 | 1.40 |
27 | β-Copaene | 1423 | 0.17 | - | - | - | - | - | - | - | - | - |
28 | β-Gurjunene | 1434 | 0.07 | - | - | - | - | - | - | - | - | - |
29 | α-Guaiene | 1442 | 0.31 | 0.21 | - | - | - | - | - | - | - | - |
30 | γ-Muurolene | 1476 | 0.05 | - | - | - | - | - | - | - | - | - |
31 | Germacrene D | 1484 | 0.17 | - | - | - | - | - | - | - | - | - |
32 | Caryophyllene oxide | 1576 | 0.12 | - | - | - | - | - | - | - | - | - |
Monoterpene hydrocarbons | 4.95 | 4.36 | 4.07 | 3.50 | 4.10 | 4.20 | 4.04 | 4.56 | 4.37 | 4.03 |
Oxygenated monoterpenes | 82.94 | 87.33 | 88.08 | 89.38 | 88.73 | 88.75 | 88.94 | 88.48 | 89.06 | 88.03 |
Phenolic monoterpenes | 0.15 | - | - | - | - | - | - | - | - | - |
Sesquiterpene hydrocarbons | 3.66 | 2.10 | 1.88 | 1.20 | 1.27 | 1.25 | 1.25 | 1.57 | 1.53 | 1.40 |
Oxygenated sesquiterpenes | 0.12 | - | - | - | - | - | - | - | - | - |
Others | 7.02 | 6.19 | 5.96 | 5.92 | 5.90 | 5.80 | 5.77 | 5.10 | 5.03 | 6.54 |
Total identified | 98.84 | 99.98 | 99.99 | 100 | 100 | 100 | 100 | 99.71 | 99.99 | 100 |
When storing the essential oil at room temperature and in glass tube containers but in direct sunlight (
Table 14), a more rapid reduction in the number of substances in the mixture is observed. For example, 3-octanol cannot be detected in the sample even after 10 days and p-cymene after 30 days. In this condition, no formation of γ-terpinene occurred unless this process was completed during the first 10 days and the substance was not detected. After the gradual loss of substances, the final result is that the mixture consists of the same six substances (as in the previous condition) in the last four measurements, and the percentage of isomenthol increased to 52.33%.
During the stability experiment at high temperatures of 35 °C and 45 °C in glass ampoules (
Table 15), the essential oil composition remains relatively stable. Apart from the loss of volatile components in small concentrations observed in the first measurement, only p-cymene, δ-elemene, and α-guaiene could no longer be detected in the mixture after 3 months. Formation of γ-terpinene is observed only at 35 °C, probably because at 45 °C the process of its formation and degradation takes place at a higher rate, and as a result, its occurrence within the analyses may have been overlooked. In the final measurement after 80 days, the essential oil composition at both temperatures consists of 13 compounds (limonene, isopulegol, menthone, isomenthone, neomenthol, iso-menthol, neoisomenthol, α-terpineol, pulegone, isopiperitone, menthyl acetate, β-bourbonene, and
trans-caryophyllene), and the percentage of iso-menthol increased to 45.95% at 35 °C and 47.10% at 45 °C from 36.59% in the initial sample.
At the same temperatures (35 °C and 45 °C) but in glass tubes (
Table 14), the alteration of the composition occurs at a higher rate. No formation of γ-terpinene was observed at both temperature conditions. The samples after 3 months (Day 80) consisted of the same six substances (limonene, menthone, isomenthone, neomenthol, isomenthol, and menthyl acetate), and the percentage of isomenthol increased to 50.48% at 35 °C and 50.38% at 45 °C from 36.59% in the initial sample.
In the refrigerator at low temperatures (4 °C and −20 °C) (
Table 15), the number of substances in the essential oil appeared to be better preserved compared to the rest of the conditions (at room and high temperatures) regardless of the container. At 4 °C after 6 months, the composition remained almost stable, consisting of eight substances (limonene, menthone, isomenthone, neomenthol, isomenthol, α-terpineol, menthyl acetate, and
trans-caryophyllene). The percentage of iso-menthol increased to 50.71% after 6 months. At 4 °C, in both metal containers and glass ampoules, isopulegol, neoisomenthol, pulegone, isopiperitone, and β-bourbonene are additionally preserved. The percentage of isomenthol in these conditions increased less in comparison with higher temperatures (23 °C, 35 °C, and 45 °C) and specifically to 43.26% and 43.41% for metal containers and glass ampoules, respectively. Finally, at −20 °C in glass tubes, the same substances are preserved as at 4 °C in the same container, but again less than those remaining in comparison to metal containers and glass ampoules, suggesting that the type of container affects the stability more significantly at low temperatures than the temperature itself. The concentration of isomenthol increases in this condition (−20 °C) to 49.01%. Finally, the formation of γ-terpinene was not recorded at 4 °C or −20 °C, but this does not mean that the process did not take place at some point during the experiments as less frequent measurements were performed.
The initial sample of
M. ×
piperita essential oil was clear with a very slight yellowish tint. When it was stored in various conditions, no great difference in its appearance was observed, apart from the sample placed in a glass tube with a cap at 45 °C, which after 3 months turned clear yellow. In the same container at 35 °C, the change to yellow was less intense but clearly visible (
Figure 2).
Figure 2.
Photo-documentation on different days (0, 40, 80, 170) of selected essential oils (O. vulgare, T. vulgaris, M. spicata and M. x piperita) after storage in various conditions: A. at room temperature in glass tubes sealed with cap; B. in direct sunlight exposure in glass tubes sealed with cap; C. at 4 °C in glass tubes sealed with cap; D. at 35 °C in glass tubes sealed with cap; E. at 45 °C in glass tubes sealed with cap; F. at 35 °C in sealed glass ampoules; G. at 45 °C in sealed glass ampoules.
Figure 2.
Photo-documentation on different days (0, 40, 80, 170) of selected essential oils (O. vulgare, T. vulgaris, M. spicata and M. x piperita) after storage in various conditions: A. at room temperature in glass tubes sealed with cap; B. in direct sunlight exposure in glass tubes sealed with cap; C. at 4 °C in glass tubes sealed with cap; D. at 35 °C in glass tubes sealed with cap; E. at 45 °C in glass tubes sealed with cap; F. at 35 °C in sealed glass ampoules; G. at 45 °C in sealed glass ampoules.