3.1. Dry Matter, Total Fat and Fatty Acid Profile of Teff Varieties
The dry matter and crude fat content, and fatty acid profiles of teff varieties are presented in
Table 2. The dry matter content of teff samples ranged between 89.00 and 90.38 g/100 g, where the content in DZ-Cr-387 was significantly lower (
p < 0.05) than the other teff varieties. The crude fat content was in the range from 2.92 to 3.34 g/100 g DM, which was slightly higher than the content in barley, maize and wheat, but lower than that reported in sorghum and oat [
23,
24]. The result is consistent with the value detected by Agza et al. [
25] but lower than that reported by Collar and Angioloni [
26]. The fat content in DZ-Cr-387 (3.34 g/100 g DM) was significantly higher (
p < 0.05) than the other teff varieties. On the other hand, the total fatty acid content of this variety was significantly higher (
p < 0.05) than that found in DZ-01-1278, DZ-01-1681, DZ-01-2053 and DZ-01-2675 varieties. More than 25 fatty acids were identified in the studied teff varieties. However, the most abundant fatty acids were linoleic (C18:2,
cis,
cis-9,12), oleic (C18:1
cis 9), palmitic (C16:0), α-linolenic (C18:3, all cis-9,12,15) and stearic (C18:0) in decreasing order (
Table 2).
The content of palmitic acid (C16:0) in DZ-Cr-387 and oleic acid (C18:1
cis 9) in DZ-01-1278 and DZ-01-99 were significantly lower (
p < 0.05) than that obtained in other teff varieties. DZ-01-2423 variety had higher oleic acid (C18:1
cis 9) content whereas both DZ-01-2423 and DZ-01-2675 varieties had lower linoleic acid (C18:2,
cis,
cis-9,12) content compared to the remaining teff varieties at
p < 0.05. All teff varieties did not reveal significant differences (
p > 0.05) in omega 3 fatty acid (α-linolenic acid (C18:3, all
cis-9,12,15)) content. The content of linoleic acid in the studied teff varieties was lower than that reported for barley and wheat but comparable with that reported for sorghum and oat. On the other hand, teff had higher α-linolenic acid content than barley, sorghum, millet, wheat, rice, maize and oat [
23,
24,
27]. Alpha linoleic acid, which is an omega 3 fatty acid, is a precursor for the higher n-3 polyunsaturated fatty acids (PUFAs) (eicosapentaenoic acid, docosapentaenoic and docosahexanoic acid). Thus, the presence of higher α-linolenic acid in staple foods will protect consumers from the risk of cardiovascular disease, atherosclerosis and hypertension [
28].
Table 3 shows the proportion of fatty acid groups, along with the atherogenic and thrombogenic indices of teff varieties. The total saturated fatty acid level ranged from 22.35 to 24.33%; the lowest was obtained in DZ-Cr-387 variety and the highest in DZ-01-1278. Total unsaturated fatty acids ranged from 75.45 to 76.83%, but no statistical difference among the varieties was found, and approximately two-thirds of total unsaturated fatty acids were PUFAs. The lowest percentage of PUFAs was found in DZ-Cr-387 and the highest was found in DZ-01-2423. The presence of a high proportion of PUFAs in oils is a desirable attribute for application in healthy food product development [
29].
The ratio of omega 6 to omega 3 fatty acids was in the range of 5.86 to 7.04; the highest was for DZ-01-2675 and the lowest was for DZ-01-1681. The result was lower than that reported for other cereals such as oat, barley, wheat, sorghum, rice and buckwheat (~14–39), which is beneficial, taking into consideration the optimal recommendation of the Mediterranean diet (1–2:1) [
23,
24,
30] to reduce cardiovascular diseases. However, according to the European Food Safety Authority opinion, there is no strict recommendation, but it was advised that the intake of n-6 and n-3 should be 4 and 0.5%, respectively, of the total dietary energy [
31].
The thrombogenicity index (TI) and atherogenicity index (AI) of teff were in the range from 0.38 to 0.41 and 0.23 to 0.25, respectively (
Table 3). The TI of teff was higher than quinoa (0.20), sunflower oil (0.20), rapeseed (0.10), peanut, sesame and olive (0.33–0.34) and oat (0.03–0.34), but lower than rice bran (0.49), buckwheat (0.52),
Amaranthus hypochondriacus and
Amaranthus cruentus (0.65–0.71), palm oil (1.92) and coconut oil (3.98). On the other hand, the AI of teff was higher than that of sunflower (0.08) and slightly higher than oat (0.17–0.19), but lower than
Amaranthus hypochondriacus (0.31), palm oil (0.97) and coconut oil (14.71) [
30,
32]. The low TI and AI values of teff compared to the oils of some cereals and oilseeds enable the crop to be considered as a healthy alternative for nutraceutical food development.
3.2. Total Fat and Fatty Acid Profile of Amaranth Varieties
Table 4 presents the dry matter and total fat content, and fatty acid profile of amaranth. The dry matter content was in the range of 88.83 and 89.23 g/100 g for brown and white amaranth, respectively. The crude fat content of white amaranth (9.14 mg/100 g DM) was significantly higher (
p < 0.05) than that of the other two varieties, which was 8.44 mg/100 g DM and 8.28 mg/100 g DM, for brown and red amaranth, respectively. The result shows that the fat content of amaranth was higher than that found in other pseudocereals such as teff (2.57 g/100 g), quinoa (6.30 g/100 g) [
25], buckwheat (2.7 g/100 g) [
24], millet (3.38–6.49 g/100 g) [
33] and
Amaranthus caudatus from the Spanish market (5.81 g/100 g) [
26]. Total fatty acid content ranged between 5409 and 6111 mg/100 g DM; however, there was no statistically significant difference (
p > 0.05) among the varieties considered. The major fatty acids measured in amaranth, in decreasing order, were linoleic (C18:2,
cis, cis-9,12), oleic (C18:1
cis 9), palmitic (C16:0), stearic (C18:0) and vaccenic (C18:1
cis 11) (
Table 4).
The content of linoleic acid in red amaranth (46.39%) was approximately 10% higher than that found in white (35.73%) and brown (36.55%) amaranth varieties. The content in the former variety was comparable with that found in teff varieties (
Table 2), higher than that reported for oat (34.6–38.2%) [
30] but lower than that reported for foxtail millets (~67%) [
33]. The increased level of linoleic acid in red amaranth is compensated for by a decrease in oleic acid by approximately 10% compared to the other varieties (
Table 4). Linoleic acid is a precursor for the higher omega 6 fatty acid called arachidonic acid within the body. Hence, the presence of a reasonable amount of linoleic acid in the diet minimizes the risk of cardiovascular disease (CVD) [
34].
The content of vaccenic acid in amaranth ranged between 1.20 and 1.44%; red amaranth had significantly higher (
p < 0.05) levels than brown and white amaranth. The content of stearic (C18:0) acid was also significantly lower (
p < 0.05) for red amaranth (2.43%) with respect to white (3.50%) and brown (3.27%) varieties. The content in the latter varieties was comparable to that found in the teff varieties considered in the present study (
Table 1). The content of stearic acid in amaranth varieties (2.43–3.5%) was by far higher than that reported in other pseudocereals such as buckwheat (2.00%) and quinoa (0.59%) [
24] but lower than that reported in millet (5.45–8.24%) [
33].
The content of palmitic acid (C16:0) in amaranth was in the range of 20.81 to 21.09% with no statistical difference among the varieties at
p > 0.05. However, the result was higher than that found in teff (16.40–18.16%) (
Table 2), millet (6.65–7.86%) [
33], quinoa (9.18%) [
24] and maize (12.61–16.22%) [
27], but it was comparable with that reported in buckwheat (19.96%) [
24] and oat (21.4–22.8%) [
30]. The content of omega 3 fatty acid was less than 1% in all amaranth varieties. This finding is in accordance with data reported by León-Camacho et al. [
35].
Table 5 shows the proportion of fatty acid groups and the atherogenic and thrombogenic indices of amaranth varieties. The total saturated fatty acid content for red amaranth (27.74%) was significantly lower than that of brown amaranth (28.52%) (
p < 0.05), while there was no statistical difference between the contents of unsaturated fatty acid for all amaranth varieties. Moreover, the content of MUFA was lower in red (24.71%) than in white (35.16%) and brown (34.16%) amaranth. On the contrary, the content of PUFA was higher for red amaranth (47.48%) with respect to white (36.47%) and brown (37.30%) amaranth, but it was lower compared to that found in teff (48.11–50.22%) (
Table 3). The presence of a lower content of PUFAs in amaranth, compared to teff, can improve the oxidative and shelf stability of amaranth flour compared to teff flour.
The omega 6 to omega 3 ratio was in the range of 54.90 to 68.63; the highest value was obtained for white amaranth, followed by brown amaranth. The ratio was much higher than that reported for most cereals, such as barley, oat, rice, sorghum and wheat [
23], maize, rye, buckwheat and quinoa [
24] which had an n6 to n3 ratio in the range of 6.0 to 32.7. Brown and red amaranth had a comparable n6 to n3 ratio with millet [
24]. The PUFA:SFA ratio of amaranth was relatively higher than that of teff, especially the white and brown amaranth varieties, which fell under the recommended range (1.0–1.5) for a diet helping to reduce cardiovascular disease [
36].
The thrombogenicity index (TI) of amaranth was between 0.65 to 0.70 (
Table 5), and the lowest and highest values were obtained for the red and white variety, respectively. The atherogenicity index (AI) of amaranth was the same for all varieties (0.31). The TI values of amaranth varieties were in accordance with those reported by Dubois et al. [
32] for
Amaranthus hypocondriacus and
Amaranthus cruentus (0.65–0.71), but higher than that obtained for teff in the present study (
Table 3), quinoa (0.2), oats (0.30–0.34) and buckwheat (0.52) [
30,
32]. On the other hand, the AI values of amaranth varieties were in agreement with those reported by Dubois et al. [
32] for
Amaranthus cruentus (0.31), higher than oats (0.17–0.19) and sunflower (0.08), but lower than palm (0.97) and coconut oil (14.71) [
30,
32].
3.3. Correlation Analysis
Table 6 shows how the main fatty acids were correlated in both teff and amaranth varieties. Palmitic acid was significantly negatively correlated with stearic acid (
r = −0.443,
p = 0.044) and oleic acid (
r = −0.691,
p = 0.001) for teff. However, the correlation of palmitic acid with both stearic and oleic acids was positive, although it was not statistically significant for amaranth. Stearic acid was significantly positively correlated with oleic acid (
r = 0.922,
p = 0.000) and negatively correlated with linoleic acid (
r = 0.914,
p = 0.001) in amaranth. Oleic acid was significantly negatively correlated with linoleic acid at
p = 0.001 and
p = 0.000 for teff and amaranth, respectively. Alpha-linolenic acid was significantly correlated with oleic acid (
r = −0.753,
p = 0.019) and linoleic acid (
r = 0.761,
p = 0.017) in amaranth. Hlinková et al. [
37] reported a negative correlation between oleic and linoleic acid in amaranth. Similarly, in the present study, a higher negative correlation was obtained between oleic and linoleic acid in amaranth. On the other hand, the lowest positive correlation was obtained between stearic and α-linolenic acid in teff. Pearson correlation analysis showed that teff and amaranth had different biosynthetic pathways for the synthesis of the major fatty acids, as the direction of the correlation was the opposite for the majority of fatty acid pairs where correlation was established.