Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics
Abstract
:1. Introduction
2. Results
2.1. Identification and Relative Quantification of Differential Volatile Compounds
2.1.1. Identification of Differential Volatile Compounds
2.1.2. Relative Quantification of Differential Volatile Compounds
2.2. PCA
2.3. PLS–DA
3. Discussion
4. Materials and Methods
4.1. Tea Samples, Reagents and Instruments
4.2. HS/GC-MS Method
4.2.1. Headspace Injection Method for Tea Sample
4.2.2. GC-MS Condition
4.2.3. Headspace Sampling Method and Retention Index Calculation of N-Alkanes
4.3. Analysis
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
Abbreviations
HS/GC-MS | Headspace sampling combined with gas chromatography–mass spectrometry |
CAS | Chemical abstracts service |
MS | Mass spectrometry |
SD | Standard deviation |
PCA | Principal component analysis |
PLS-DA | Partial least squares discrimination analysis |
HCA | Hierarchical cluster analysis |
VIP | Variable important for the projection |
ANOVA | Analysis of variance |
References
- Chen, M.X. Development status and countermeasure of Tieguanyin industrialization in Anxi. Mod. Agric. Sci. Tech. 2018, 15, 262–264. (In Chinese) [Google Scholar]
- Lin, D.L.; Zhang, X.B.; Wen, K.; Chen, L.; Sun, W.J.; Lin, R.X.; Chen, W.Q.; Huang, H.S.; Chen, Q.B.; Lin, X.B.; et al. 2013 Oolong Tea Part 2: Tieguanyin; GB/T 30357.2; Standards Press of China: Beijing, China, 2013. (In Chinese) [Google Scholar]
- Chen, L.; Lin, Q.X.; Zhang, Y.G.; Chen, J.; Wang, L.L.; Yu, W.Q.; You, Z.M. Aroma profiling of Tieguanyin Oolong tea with different flavor characteristics based on chemical pattern recognition. Tea Sci. 2018, 38, 253–262. (In Chinese) [Google Scholar]
- Shi, Z.P. Tea Evaluation and Inspection, 4th ed.; China Agriculture Press: Beijing, China, 2010; p. 21. (In Chinese) [Google Scholar]
- Lv, S.D.; Wu, Y.S.; Jiang, Y.F.; Meng, Q.X. Comparative analysis of aroma characteristics of Oolong tea from different geographical regions. Food Sci. 2014, 35, 146–153. (In Chinese) [Google Scholar]
- Wang, W.J. Research progress of tea quality identification technology. China Tea Process. 2006, 3, 40–42. (In Chinese) [Google Scholar]
- Jing, J.; Shi, Y.; Zhang, Q.; Wang, J.; Ruan, J. Prediction of Chinese green tea ranking by metabolite profiling using ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF/MS). Food Chem. 2017, 221, 311–316. [Google Scholar] [CrossRef]
- Capone, S.; Tufariello, M.; Francioso, L.; Montagna, G.; Casino, F.; Leone, A.; Siciliano, P.A. Aroma analysis by GC/MS and electronic nose dedicated to Negroamaro and Primitivo typical Italian Apulian wines. Sens. Actuators B Chem. 2013, 179, 259–269. [Google Scholar] [CrossRef]
- Song, J.; Bi, J.; Chen, Q.; Wu, X.; Lyu, Y.; Meng, X. Assessment of sugar content, fatty acids, free amino acids, and volatile profiles in jujube fruits at different ripening stages. Food Chem. 2019, 270, 344–352. [Google Scholar] [CrossRef]
- Cui, S.; Wang, J.; Yang, L.; Wu, J.; Wang, X. Qualitative and quantitative analysis on aroma characteristics of ginseng at different ages using E-nose and GC-MS combined with chemometrics. J. Pharm. Biomed. Anal. 2015, 102, 64–77. [Google Scholar] [CrossRef]
- Li, Q.; Yu, X.; Xu, L.; Gao, J.M. Novel method for the producing area identification of Zhongning Goji berries by electronic nose. Food Chem. 2016, 221, 1113. [Google Scholar] [CrossRef] [PubMed]
- Gong, H.; Yang, Z.; Liu, M.; Shi, Z.; Li, J.; Chen, W.; Qiao, X. Time-dependent categorization of volatile aroma compound formation in stewed Chinese spicy beef using electron nose profile coupled with thermal desorption GC-MS detection. Food Sci. Hum. Wellness 2017, 6, 137–146. [Google Scholar] [CrossRef]
- Qi, D.; Miao, A.; Cao, J.; Wang, W.; Chen, W.; Pang, S.; He, X.; Ma, C. Study on the effects of rapid aging technology on the aroma quality of white tea using GC- MS combined with chemometrics: In comparison with natural aged and fresh white tea. Food Chem. 2018, 265, 189–199. [Google Scholar] [CrossRef]
- Xiaohua, C.; Dejing, C.; Hai, J.; Haiyan, S.; Chen, Z.; Hua, Z.; Xinsheng, L.; Fei, Y.; Chen, C.; Zhimin, X. Aroma Characterization of Hanzhong Black Tea (Camellia sinensis) Using Solid Phase Extraction Coupled with Gas Chromatography–Mass Spectrometry and Olfactometry and Sensory Analysis. Food Chem. 2019, 274, 130–136. [Google Scholar]
- Kumar, R.; Sharma, V. Chemometrics in forensic science. Trends Analyt. Chem. 2018, 105, 191–201. [Google Scholar] [CrossRef]
- Bevilacqua, M.; Bro, R.; Marini, F.; Rinnan, Å.; Rasmussen, M.A.; Skov, T. Recent chemometrics advances for foodomics. Trends Anal. Chem. 2017, 96, 42–51. [Google Scholar] [CrossRef]
- Granato, D.; Santos, J.S.; Escher, G.B.; Ferreira, B.L.; Maggio, R.M. Use of principal component analysis (PCA) and hierarchical cluster analysis (HCA) for multivariate association between bioactive compounds and functional properties in foods: A critical perspective. Trends Food Sci. Tech. 2018, 72, 83–90. [Google Scholar] [CrossRef]
- Chen, Y.; Deng, J.; Wang, Y.; Liu, B.; Ding, J.; Mao, X.; Zhang, J.; Hu, H.; Li, J. Study on discrimination of white tea and albino tea based on near-infrared spectroscopy and chemometrics. J. Sci. Food Agric. 2014, 94, 1026–1033. [Google Scholar] [CrossRef]
- Dai, W.; Qi, D.; Xie, D.; Tan, J.; Yang, T.; Lv, H.; Guo, L.; Zhang, Y.; Zhu, Y.; Peng, Q.; et al. Nontargeted Analysis Using Ultraperformance Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry Uncovers the Effects of Harvest Season on the Metabolites and Taste Quality of Tea (Camellia sinensis L.). J. Sci. Food Agric. 2015, 63, 9869–9878. [Google Scholar] [CrossRef]
- Lv, S.; Wu, Y.; Wei, J.; Lian, M.; Wang, C.; Gao, X.; Meng, Q. Application of gas chromatography-mass spectrometer and chemometrics methods for assessing volatile profiles of Pu-erh tea with different processing ways and ageing year. Rsc Adv. 2015, 5, 87806–87817. [Google Scholar] [CrossRef]
- Gutierrez-Osuna, R. Pattern analysis for machine olfaction: A review. IEEE Sens. J. 2002, 2, 189–202. [Google Scholar] [CrossRef]
- Hidalgo, M.J.; Pozzi, M.T.; Furlong, O.J.; Marchevsky, E.J.; Pellerano, R.G.; Marchesky, E.J. Classification of organic olives based on chemometric analysis of elemental data. Microchem. J. 2018, 142, 30–35. [Google Scholar] [CrossRef]
- Toraman, H.E.; Abrahamsson, V.; Vanholme, R.; Van Acker, R.; Ronsse, F.; Pilate, G.; Boerjan, W.; Van Geem, K.M.; Marin, G.B. Application of Py-GC/MS coupled with PARAFAC2 and PLS-DA to study fast pyrolysis of genetically engineered poplars. J. Anal. Appl. Pyrolysis. 2018, 129, 101–111. [Google Scholar] [CrossRef]
- Zhou, J.S. A Combination of LC-MS Techniques and Chemometrics in Application of Different Types of Tea. Master’s Thesis, Kunming University of Science and Technology, Kunming, China, May 2014. (In Chinese). [Google Scholar]
- Sharma, V.; Kumar, R. Trends of chemometrics in bloodstain investigations. Trends Anal. Chem. 2018, 107, 181–195. [Google Scholar] [CrossRef]
- Liu, B.Q.; Chen, X.Q.; Wu, X.G.; Zhang, W.; Wang, Z.H. Study of Pu’er raw materials grade classification by PCA and PLS-DA. J. Tea Sci. 2015, 35, 179–184. (In Chinese) [Google Scholar]
- Hong, X.; Wang, J.; Qi, G. E-nose combined with chemometrics to trace tomato-juice quality. J. Food Eng. 2015, 149, 38–43. [Google Scholar] [CrossRef]
- Wang, Y.; Yang, C.; Li, S.; Yang, L.; Wang, Y.; Zhao, J.; Jiang, Q. Volatile characteristics of 50 peaches and nectarines evaluated by HP–SPME with GC-MS. Food Chem. 2009, 116, 356–364. [Google Scholar] [CrossRef]
- Liu, Y.; Ge, L.Q.; Wang, Y.X. Study of Principal Components Analysis of volatile compounds and origin discrimination in Lu Mountain Clouds-Mist Tea. Food Sci. 2017, 38, 60–67. (In Chinese) [Google Scholar]
- Gu, S.Q.; Wang, X.C.; Tao, N.P.; Zhang, J.J. Analysis of aroma compounds from different edible parts of Chinese Mitten Crab (Eriocheirsinensis) by HS-SPME-GC-MS and E-Nose. Food Sci. 2013, 34, 239–244. (In Chinese) [Google Scholar]
- Zhang, Y.; Li, W.F.; Xiao, B. Analysis of volatile components of twenty-five Hunan and Shanxi Fuzhuan tea samples by HS-SPME-GC-MS. J. Northwest AF Univ. (Nat. Sci. Ed.) 2017, 45, 151–160. (In Chinese) [Google Scholar]
- Zhang, Z.Z.; Yang, Y.F.; Sun, H.; Hong, P.; Huang, G.L.; Jiang, Z.D.; Chen, F.; Du, X.P.; Hu, Y.; Ni, H. Volatile Components and Sensory Characteristics of Three Fresh Scent-Flavor Tieguanyin Teas. J. Jimei Uni. (Nat. Sci.) 2016, 21, 175–183. (In Chinese) [Google Scholar]
Sample Availability: Standard samples of 5 grades Nongxinag Tieguanyin teas are available from the authors. |
No. | Compounds | CAS a | MS b | RI(cal)/RI(ref) c | Relative Content (Mean ± SD)/% d | ||||
---|---|---|---|---|---|---|---|---|---|
K110 | K101 | K102 | K103 | K104 | |||||
1 | methyl chloride | 74-87-3 | ** | -/- | 2.73 ± 0.1a | 1.76 ± 0.26c | 2.88 ± 0.22a | 2.35 ± 0.08b | 0.92 ± 0.06d |
2 | oxetane | 503-30-0 | * | -/- | 3.01 ± 0.16abc | 3.13 ± 0.15ab | 2.78 ± 0.18c | 2.95 ± 0.19bc | 3.27 ± 0a |
3 | methyl acetate | 79-20-9 | * | -/- | 11.17 ± 0.35a | 7.03 ± 0.43b | 5.83 ± 0.65c | 5.79 ± 0.5c | 11.83 ± 0.15a |
4 | dimethyl sulfide | 75-18-3 | ** | -/- | 11.49 ± 0.97a | 7.52 ± 0.79b | 7.09 ± 0.36b | 7.35 ± 0.37b | 8.13 ± 0.1b |
5 | 2-methylfuran | 534-22-5 | * | -/604 | 2.84 ± 0.13c | 3.33 ± 0.04b | 3.66 ± 0.13a | 3.4 ± 0.18ab | 3.48 ± 0.17ab |
6 | hexane | 110-54-3 | ** | -/- | 2.42 ± 0.1bc | 2.52 ± 0.13ab | 2.58 ± 0.09ab | 2.66 ± 0.09a | 2.28 ± 0.06c |
7 | methyl propanoate | 554-12-1 | * | -/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 1.28 ± 0.21 |
8 | cis,cis-2,4-hexadiene | 6108-61-8 | * | -/- | 0.33 ± 0.01 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
9 | isovaleraldehyde | 590-86-3 | ** | -/656 | 0.71 ± 0b | 0.69 ± 0.03b | 0.85 ± 0.04a | 0.88 ± 0.05a | 0.48 ± 0.01c |
10 | 2-methylbutanal | 96-17-3 | ** | -/665 | 6.77 ± 0.26c | 6.08 ± 0.18d | 7.93 ± 0.19b | 8.71 ± 0.32a | 3.82 ± 0.06e |
11 | 1-penten-3-ol | 616-25-1 | * | -/681 | 6.85 ± 0.2d | 13.91 ± 0.34c | 15.92 ± 0.68a | 14.67 ± 0.33b | 6 ± 0.12e |
12 | 2-ethylfuran | 3208-16-0 | * | -/701 | 3.1 ± 0.09c | 4.6 ± 0.28a | 4.73 ± 0.13a | 4.88 ± 0.28a | 3.6 ± 0.34b |
13 | isocyanoethane | 624-79-3 | * | -/- | 1.08 ± 0.09 | 1.12 ± 0.01 | 0.85 ± 0.02 | 0.88 ± 0.03 | 1.57 ± 0.1 |
14 | isovaleronitrile | 625-28-5 | ** | -/- | 0.37 ± 0.01b | 0.38 ± 0.04b | 0.26 ± 0.01c | 0.3 ± 0.02c | 0.45 ± 0.03a |
15 | tiglic aldehyde | 1115-11-3 | * | -/744 | 0.29 ± 0.02 | 0.41 ± 0.05 | 0.35 ± 0.01 | 0.36 ± 0.02 | 0.46 ± 0.02 |
16 | 2-methyl-3-pentanone | 565-69-5 | * | -/- | 0 ± 0 | 0.18 ± 0.02 | 0.17 ± 0.01 | 0.12 ± 0 | 0.22 ± 0.03 |
17 | 2-methylidenecyclopentan-1-ol | 20461-31-8 | * | -/- | 1.41 ± 0.06e | 2.23 ± 0.11c | 2.44 ± 0.07b | 2.71 ± 0.08a | 1.97 ± 0.03d |
18 | toluene | 108-88-3 | ** | -/773 | 2.3 ± 0.02b | 2.3 ± 0.19b | 1.93 ± 0.24c | 2.04 ± 0.07bc | 5.66 ± 0.12a |
19 | 2-cyclopropylethanol | 2566-44-1 | * | -/- | 1.38 ± 0.04 | 3.28 ± 0.07 | 3.27 ± 0.23 | 3.38 ± 0.21 | 0 ± 0 |
20 | unknown-1 | - | - | -/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.31 ± 0.01 |
21 | mesityl oxide | 141-79-7 | * | -/- | 0.61 ± 0.02c | 0.75 ± 0.06b | 1.2 ± 0.09a | 1.19 ± 0.04a | 0.71 ± 0.03bc |
22 | hexanal | 66-25-1 | ** | -/801 | 1.03 ± 0.03b | 0.95 ± 0.04b | 0.94 ± 0.05b | 0.93 ± 0.05b | 1.31 ± 0.1a |
23 | 2-methyltetrahydrofuran-3-one | 3188-00-9 | ** | 805/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.31 ± 0.02 |
24 | 1-ethylpyrrole | 617-92-5 | * | 808/- | 12.27 ± 0.7a | 8.66 ± 0.08b | 6.94 ± 0.43c | 7.05 ± 0.01c | 1.63 ± 0.09d |
25 | furfural | 98-01-1 | ** | 830/- | 0.3 ± 0.02 | 0.92 ± 0.09 | 0.71 ± 0.05 | 0.55 ± 0.06 | 7.08 ± 0.44 |
26 | methyl formate | 107-31-3 | * | 835/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 4.96 ± 0.82 |
27 | 2,5,5-trimethyl-1-hexen-3-yne | 37439-53-5 | * | 837/- | 0.31 ± 0.01 | 0.78 ± 0.03 | 0.63 ± 0.05 | 0.84 ± 0.05 | 0 ± 0 |
28 | 3,4,5-trimethylcyclopent-2-en-1-one | 55683-21-1 | * | 847/- | 0.05 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
29 | leaf alcohol | 928-96-1 | * | 849/853 | 0.11 ± 0.01 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
30 | 2-methyl-3-octyne | 55402-15-8 | * | 852/- | 0.09 ± 0c | 0.37 ± 0.02b | 0.33 ± 0.02b | 0.45 ± 0.07a | 0.44 ± 0.03a |
31 | 2,2-dichloroacetophenone | 2648-61-5 | * | 854/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.5 ± 0.02 |
32 | p-Xylene | 106-42-3 | * | 863/- | 0.94 ± 0.01c | 1.27 ± 0.02b | 0.79 ± 0.04d | 0.81 ± 0.06d | 1.75 ± 0.06a |
33 | capronitrile | 628-73-9 | * | 874/- | 0 ± 0 | 0.07 ± 0.01 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
34 | 2,6-dimethyl-1,5-heptadiene | 6709-39-3 | * | 878/- | 0 ± 0 | 0.08 ± 0.01 | 0.09 ± 0.01 | 0.15 ± 0.01 | 0.29 ± 0.02 |
35 | unknown-2 | - | - | 887/- | 0.33 ± 0.01 | 0.68 ± 0.05 | 0.67 ± 0.03 | 0.68 ± 0.02 | 0.93 ± 0.01 |
36 | cis-4-heptenal | 6728-31-0 | * | 898/901 | 0.05 ± 0c | 0.11 ± 0a | 0.05 ± 0.01c | 0.06 ± 0.01b | 0.05 ± 0.01c |
37 | heptanal | 111-71-7 | ** | 901/903 | 0.08 ± 0.01bc | 0.1 ± 0.01a | 0.07 ± 0.01c | 0.08 ± 0.01c | 0.1 ± 0.01ab |
38 | 2,3,4-trimethyl-1H-pyrrole | 3855-78-5 | * | 903/- | 0.65 ± 0.03 | 0.55 ± 0.04 | 0.46 ± 0.01 | 0.42 ± 0.02 | 0.16 ± 0 |
39 | 1-(furan-2-yl)ethanone | 1192-62-7 | * | 909/902 | 0.15 ± 0.01d | 0.37 ± 0.08b | 0.71 ± 0.03a | 0.42 ± 0.02b | 0.26 ± 0.02c |
40 | 1,1-dimethyl-4-methylenecyclohexane | 6007-96-1 | * | 910/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.29 ± 0.02 |
41 | unknown-3 | - | - | 912/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.08 ± 0.01 |
42 | 2-amino-5-methylpyridine | 1603-41-4 | * | 917/- | 0.92 ± 0.04 | 1.06 ± 0.07 | 0.68 ± 0.02 | 0.65 ± 0.05 | 0.25 ± 0 |
43 | methyl hexoate | 106-70-7 | ** | 922/925 | 0 ± 0c | 0.27 ± 0.01a | 0.2 ± 0.01b | 0.21 ± 0.02b | 0.26 ± 0.01a |
44 | unknown-4 | - | - | 928/- | 0.09 ± 0cd | 0.08 ± 0d | 0.22 ± 0.01a | 0.1 ± 0.01b | 0.1 ± 0.01bc |
45 | unknown-5 | - | - | 937/- | 0.03 ± 0d | 0 ± 0e | 0.05 ± 0c | 0.06 ± 0.01b | 0.11 ± 0a |
46 | 1-butylpyrrole | 589-33-3 | * | 940/- | 0.07 ± 0a | 0.06 ± 0a | 0.03 ± 0b | 0.07 ± 0.01a | 0.03 ± 0.01b |
47 | (+)-camphene | 79-92-5 | * | 943/955 | 0.04 ± 0d | 0.05 ± 0d | 0.05 ± 0c | 0.06 ± 0b | 0.08 ± 0.01a |
48 | unknown-6 | - | - | 952/- | 0.04 ± 0d | 0.05 ± 0.01c | 0.05 ± 0c | 0.07 ± 0b | 0.21 ± 0.01a |
49 | 1-chloroheptane | 629-06-1 | * | 955/- | 0.03 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
50 | benzaldehyde | 100-52-7 | ** | 957/957 | 0.95 ± 0.03 | 1.64 ± 0.2 | 1.42 ± 0.02 | 1.14 ± 0.04 | 3.11 ± 0.28 |
51 | cumene | 98-82-8 | * | 961/- | 0.34 ± 0.01 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
52 | methyl furan-2-carboxylate | 611-13-2 | * | 971/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.5 ± 0.01 |
53 | 1,4-decadiyne | 929-53-3 | * | 972/- | 0.13 ± 0.01c | 0.2 ± 0.02a | 0.17 ± 0.01b | 0.18 ± 0.01ab | 0 ± 0d |
54 | 1-octen-3-ol | 3391-86-4 | ** | 980/980 | 0.05 ± 0 | 0.08 ± 0 | 0.1 ± 0 | 0.11 ± 0 | 0 ± 0 |
55 | unknown-7 | - | - | 981/- | 0.06 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.15 ± 0.01 |
56 | 6-methylhept-5-en-2-one | 110-93-0 | ** | 983/982 | 1.58 ± 0.08a | 1.63 ± 0.02a | 1.4 ± 0.07b | 1.37 ± 0.06b | 0.85 ± 0.03c |
57 | 2,2,4,6,6-pentamethylheptane | 13475-82-6 | * | 986/- | 1.06 ± 0.11b | 1 ± 0.06b | 1.04 ± 0.09b | 0.94 ± 0.05b | 1.84 ± 0.06a |
58 | 2-amylfuran | 3777-69-3 | ** | 987/986 | 1.39 ± 0.18c | 1.8 ± 0.14b | 2.14 ± 0.21a | 2.28 ± 0.11a | 2.11 ± 0.08a |
59 | trans-3,5-dimethyl-1,6-octadiene | 74630-87-8 | * | 997/- | 0.19 ± 0.03d | 0.27 ± 0.04c | 0.33 ± 0.04b | 0.38 ± 0.01b | 0.47 ± 0.02a |
60 | decane | 124-18-5 | ** | 999/1000 | 0.06 ± 0.01b | 0.06 ± 0.01b | 0.07 ± 0.01b | 0.07 ± 0.01b | 0.12 ± 0.01a |
61 | (−)-perillyl alcohol | 18457-55-1 | ** | 1003/- | 0 ± 0 | 0.19 ± 0.01 | 0.22 ± 0.04 | 0.29 ± 0.02 | 0.38 ± 0.03 |
62 | 3-carene | 13466-78-9 | * | 1013/1014 | 0.09 ± 0.01c | 0.14 ± 0.02b | 0.19 ± 0.02a | 0.19 ± 0.01a | 0.21 ± 0.01a |
63 | 1-ethyl-3-methyl- benzene | 620-14-4 | * | 1015/- | 0.13 ± 0.01d | 0.18 ± 0.02c | 0.21 ± 0.02b | 0.21 ± 0.01b | 0.29 ± 0.01a |
64 | α-terpinene | 99-86-5 | * | 1018/1021 | 0.06 ± 0.01 | 0.06 ± 0.01 | 0.06 ± 0 | 0.06 ± 0.01 | 0 ± 0 |
65 | o-cymene | 527-84-4 | ** | 1020/1022 | 0.13 ± 0.02d | 0.19 ± 0.02c | 0.24 ± 0.02b | 0.27 ± 0.01b | 1.29 ± 0.04a |
66 | 2,2,4,4-tetramethyloctane | 62183-79-3 | ** | 1023/- | 0.07 ± 0.01b | 0.08 ± 0b | 0.08 ± 0.01b | 0.07 ± 0.01b | 0.11 ± 0.01a |
67 | D-limonene | 5989-27-5 | ** | 1025/1025 | 0.46 ± 0.06d | 0.75 ± 0.08c | 0.98 ± 0.12b | 1.09 ± 0.11b | 1.25 ± 0.03a |
68 | 2,2,6-trimethylcyclohexanone | 2408-37-9 | ** | 1031/1031 | 0.18 ± 0.02c | 0.31 ± 0.02a | 0.34 ± 0.02a | 0.32 ± 0.01a | 0.23 ± 0.01b |
69 | (E)-β-ocimene | 3779-61-1 | ** | 1034/1035 | 0.13 ± 0.02b | 0.12 ± 0.01b | 0.17 ± 0.02a | 0.19 ± 0a | 0.11 ± 0b |
70 | phenylacetaldehyde | 122-78-1 | ** | 1040/1040 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.04 ± 0.01 |
71 | 1,2,4-trimethylidenecyclohexane | 14296-81-2 | * | 1042/- | 0.45 ± 0.08a | 0.33 ± 0.02b | 0.24 ± 0.03b | 0.35 ± 0.02c | 0.11 ± 0.01d |
72 | (Z)-β-ocimene | 13877-91-3 | ** | 1044/1044 | 3.02 ± 0.26 | 2.69 ± 0.08 | 2.32 ± 0.09 | 2.41 ± 0.05 | 2.69 ± 0.04 |
73 | unknown-8 | - | - | 1050/- | 0 ± 0d | 0.18 ± 0.01b | 0.15 ± 0.02b | 0.42 ± 0.02a | 0.11 ± 0.01c |
74 | 2-ethyltoluene | 611-14-3 | * | 1052/- | 0.14 ± 0.01 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
75 | isophorone | 78-59-1 | * | 1055/1050 | 0.12 ± 0e | 0.27 ± 0.01c | 0.33 ± 0.02b | 0.48 ± 0.02a | 0.24 ± 0.01d |
76 | nopol | 128-50-7 | * | 1058/- | 0.06 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
77 | acetophenone | 98-86-2 | * | 1062/1062 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.1 ± 0.01 |
78 | verbenol | 473-67-6 | * | 1069/- | 0.33 ± 0.03b | 0.56 ± 0.04a | 0.67 ± 0.08a | 0.66 ± 0.04a | 0.57 ± 0.1a |
79 | 3,4,4-trimethyl-2-cyclohexen-1-one | 17299-41-1 | * | 1075/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.1 ± 0.01 |
80 | terpinolene | 586-62-9 | ** | 1081/1089 | 0.11 ± 0.01c | 0.14 ± 0.02c | 0.23 ± 0.03a | 0.23 ± 0.01a | 0.17 ± 0.01b |
81 | unknown-9 | - | - | 1086/- | 0.13 ± 0.01d | 0.2 ± 0.01c | 0.29 ± 0.03ab | 0.26 ± 0.03b | 0.32 ± 0.02a |
82 | unknown-10 | - | - | 1091/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.06 ± 0.01 |
83 | unknown-11 | - | - | 1094/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.04 ± 0.01 |
84 | unknown-12 | - | - | 1099/- | 0.28 ± 0.03b | 0.28 ± 0.02b | 0.35 ± 0.01a | 0.35 ± 0.01a | 0 ± 0c |
85 | linalool | 78-70-6 | * | 1099/1100 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.1 ± 0 |
86 | hotrienol | 20053-88-7 | * | 1102/1104 | 1.13 ± 0.02 | 0.96 ± 0.07 | 1.88 ± 0.04 | 1.81 ± 0.1 | 0 ± 0 |
87 | nonanal | 124-19-6 | ** | 1102/1105 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.02 ± 0 |
88 | N-methyl-4-anisidine | 5961-59-1 | * | 1109/1119 | 0.23 ± 0.01a | 0.19 ± 0.01b | 0.23 ± 0.01a | 0.19 ± 0.02b | 0.13 ± 0.02c |
89 | 2-ethenyl-1,1-dimethyl-3-methylenecyclohexane | 95452-08-7 | * | 1112/- | 0.91 ± 0.12 | 0.5 ± 0.05 | 0.41 ± 0.07 | 0.4 ± 0.02 | 0.72 ± 0.02 |
90 | unknown-13 | - | - | 1127/- | 0 ± 0 | 0.05 ± 0.01 | 0.08 ± 0 | 0.09 ± 0.01 | 0.06 ± 0 |
91 | benzyl cyanide | 140-29-4 | ** | 1136/1135 | 1.29 ± 0.1 | 1.07 ± 0.02 | 0.5 ± 0.03 | 0.51 ± 0.01 | 0.55 ± 0.01 |
92 | unknown-14 | - | - | 1140/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.16 ± 0.01 |
93 | 1,2,3,4-tetramethylbenzene | 488-23-3 | * | 1144/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.11 ± 0 |
94 | 3-isopropylidene-5-methyl-hex-4-en-2-one | 64149-32-2 | * | 1149/- | 0 ± 0 | 0.12 ± 0 | 0.15 ± 0.03 | 0.13 ± 0.02 | 0.06 ± 0.01 |
95 | unknown-15 | - | - | 1152/- | 0.09 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.06 ± 0.01 |
96 | propiophenone | 93-55-0 | * | 1161/- | 0 ± 0 | 0.1 ± 0 | 0.11 ± 0.02 | 0.12 ± 0 | 0.21 ± 0.01 |
97 | unknown-16 | - | - | 1164/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.06 ± 0.01 |
98 | 3-methylundecane | 1002-43-3 | ** | 1170/1176 | 0.07 ± 0b | 0.07 ± 0.01b | 0.09 ± 0a | 0.08 ± 0.01a | 0.08 ± 0.01a |
99 | unknown-17 | - | - | 1176/- | 0.26 ± 0.01b | 0.32 ± 0.01a | 0.3 ± 0.01a | 0.25 ± 0.01b | 0.12 ± 0.02c |
100 | 1,3,5,8-undecatetraene | 50277-31-1 | * | 1186/1185 | 0.13 ± 0.01 | 0.14 ± 0.01 | 0.11 ± 0.02 | 0.13 ± 0 | 0 ± 0 |
101 | safranal | 116-26-7 | ** | 1194/- | 0.09 ± 0d | 0.22 ± 0.01c | 0.31 ± 0.01a | 0.27 ± 0.01b | 0.07 ± 0.01e |
102 | dodecane | 112-40-3 | ** | 1200/1200 | 0.13 ± 0.02b | 0.12 ± 0.01b | 0.12 ± 0.02b | 0.14 ± 0.02b | 0.23 ± 0.02a |
103 | unknown-18 | - | - | 1205/- | 0.06 ± 0a | 0.04 ± 0.01b | 0.03 ± 0b | 0.06 ± 0a | 0.07 ± 0.01a |
104 | 1,2,3,4-tetramethyl-6-isopropenyl-1,4-Cyclohexadiene | - | * | 1213/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.11 ± 0.01 |
105 | β-cyclocitral | 432-25-7 | ** | 1214/1216 | 0.17 ± 0 | 0.28 ± 0.01 | 0.29 ± 0.01 | 0.25 ± 0.03 | 0.07 ± 0.01 |
106 | 6-methyl-1,3-diisopropenylcyclohexene | - | * | 1222/- | 0.02 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.07 ± 0.01 |
107 | unknown-19 | - | - | 1225/- | 0.04 ± 0c | 0.05 ± 0.01b | 0.05 ± 0b | 0.05 ± 0.01b | 0.08 ± 0.01a |
108 | cis-3-hexenyl isovalerate | 35154-45-1 | * | 1230/1235 | 0.04 ± 0 | 0.05 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
109 | unknown-20 | - | - | 1234/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.06 ± 0.01 |
110 | 2-methyl-2-phenyltridecan | 27854-41-7 | * | 1245/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.05 ± 0 |
111 | unknown-21 | - | - | 1248/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.03 ± 0 |
112 | unknown-22 | - | - | 1253/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.07 ± 0.01 |
113 | trans-1-(but-2-en-1-yl)-3,4-dimethylbenzene | 54340-86-2 | * | 1258/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.05 ± 0 |
114 | ionone | 8013-90-9 | * | 1273/- | 0.07 ± 0.01d | 0.14 ± 0.01c | 0.17 ± 0.01b | 0.15 ± 0.01b | 0.22 ± 0.01a |
115 | 1,3-dimethyl-2-butenylbenzene | 50704-01-3 | * | 1285/- | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.03 ± 0 |
116 | indole | 120-72-9 | ** | 1296/1298 | 1.38 ± 0.07 | 0.89 ± 0.12 | 0.6 ± 0.05 | 0.46 ± 0.01 | 0 ± 0 |
117 | tridecane | 629-50-5 | ** | 1300/1300 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.04 ± 0 |
118 | unknown-23 | - | - | 1308/- | 0 ± 0 | 0.12 ± 0.01 | 0.1 ± 0.02 | 0.11 ± 0 | 0.04 ± 0 |
119 | 1,1,6-trimethyl-2H-naphthalene | 30364-38-6 | * | 1346/1358 | 0.1 ± 0 | 0.26 ± 0.01 | 0.33 ± 0.03 | 0.27 ± 0 | 0.1 ± 0 |
120 | 1,1,6-trimethyl-1,2,3,4-tetrahydro- naphthalene | 475-03-6 | ** | 1347/- | 0.04 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
121 | unknown-24 | - | - | 1369/- | 0.12 ± 0.02a | 0.13 ± 0.01a | 0.13 ± 0a | 0.12 ± 0.01a | 0.1 ± 0b |
122 | cis-3-hexenyl hexanoate | 31501-11-8 | ** | 1378/1382 | 0.09 ± 0 | 0.06 ± 0 | 0.04 ± 0 | 0.03 ± 0 | 0.08 ± 0.01 |
123 | β-elemene | 515-13-9 | * | 1383/1406 | 0.04 ± 0 | 0.02 ± 0 | 0.01 ± 0 | 0.03 ± 0 | 0.02 ± 0 |
124 | tetradecane | 629-59-4 | ** | 1400/1400 | 0.06 ± 0.01c | 0.07 ± 0c | 0.11 ± 0.01a | 0.09 ± 0.01b | 0.07 ± 0.01c |
125 | (−)-α-cedrene | 469-61-4 | ** | 1408/1408 | 0.01 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.02 ± 0 |
126 | unknown-25 | - | - | 1413/- | 0.03 ± 0 | 0.02 ± 0 | 0 ± 0 | 0 ± 0 | 0.03 ± 0 |
127 | α-ionone | 127-41-3 | * | 1420/1430 | 0.02 ± 0 | 0.06 ± 0.01 | 0.06 ± 0 | 0.04 ± 0.01 | 0 ± 0 |
128 | unknown-26 | - | - | 1425/- | 0.03 ± 0c | 0.06 ± 0b | 0.07 ± 0.01a | 0.06 ± 0.01ab | 0 ± 0d |
129 | unknown-27 | - | - | 1450/- | 0.03 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.02 ± 0 |
130 | γ-muurolene | 30021-74-0 | * | 1454/1453 | 0.23 ± 0.01a | 0.17 ± 0.01b | 0.11 ± 0c | 0.11 ± 0.01c | 0.03 ± 0d |
131 | unknown-28 | - | - | 1461/- | 0.02 ± 0 | 0.03 ± 0 | 0.01 ± 0.01 | 0.02 ± 0 | 0.01 ± 0 |
132 | unknown-29 | - | - | 1464/- | 0.03 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.02 ± 0 |
133 | β-ionone | 14901-07-6 | ** | 1477/1478 | 0.06 ± 0.01 | 0.14 ± 0.01 | 0.14 ± 0.03 | 0.18 ± 0.03 | 0 ± 0 |
134 | α-curcumene | 644-30-4 | * | 1479/1483 | 0.04 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0.03 ± 0 |
135 | unknown-30 | - | - | 1483/- | 0.08 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
136 | andrographolide | 5508-58-7 | * | 1490/- | 0.16 ± 0.01 | 0.06 ± 0 | 0 ± 0 | 0 ± 0 | 0.03 ± 0.01 |
137 | γ-himachalene | - | * | 1515/1500 | 1.27 ± 0.07a | 0.48 ± 0.03b | 0.17 ± 0.01d | 0.23 ± 0.04cd | 0.28 ± 0.05c |
138 | unknown-31 | - | - | 1608/- | 0.04 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
139 | (Z)-α-bisabolene | 29837-07-8 | * | 1615/- | 0.02 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
140 | unknown-32 | - | - | 1629/- | 2.78 ± 0.1a | 1.87 ± 0.09b | 1.12 ± 0.07c | 0.95 ± 0.08d | 0.15 ± 0.04e |
141 | unknown-33 | - | - | 1633/- | 0.4 ± 0.03 | 0.09 ± 0.02 | 0 ± 0 | 0 ± 0 | 0.03 ± 0 |
142 | unknown-34 | - | - | 1651/- | 0.03 ± 0b | 0 ± 0d | 0.04 ± 0a | 0.04 ± 0a | 0.03 ± 0c |
143 | unknown-35 | - | - | 1659/- | 0.03 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 | 0 ± 0 |
No. | Compounds a | CAS b | MS c | RI(cal)/RI(ref) d | Peak Areae (Mean ± SD) * 106 | |||||
---|---|---|---|---|---|---|---|---|---|---|
K110 | K101 | K102 | K103 | K104 | ||||||
24 | 1-ethylpyrrole | + | 617-92-5 | * | 808/- | 38.34 ± 3.86a | 24.38 ± 0.96b | 20.26 ± 2.36c | 21.03 ± 0.95bc | 10.74 ± 0.77d |
140 | unknown-32 | + | - | - | 1629/- | 8.67 ± 0.41a | 5.25 ± 0.22b | 3.28 ± 0.32c | 2.83 ± 0.12c | 0.98 ± 0.24d |
5 | 2-methylfuran | - | 534-22-5 | * | -/604 | 8.84 ± 0.1d | 9.39 ± 0.37cd | 10.64 ± 0.3b | 10.14 ± 0.77bc | 22.91 ± 0.79a |
12 | 2-ethylfuran | - | 3208-16-0 | * | -/701 | 9.68 ± 0.67c | 12.97 ± 1.28b | 13.79 ± 1.15b | 14.57 ± 1.51b | 23.69 ± 2.6a |
17 | 2-methylidenecyclopentan-1-ol | - | 20461-31-8 | * | -/- | 4.38 ± 0.03e | 6.27 ± 0.12d | 7.1 ± 0.26c | 8.07 ± 0.18b | 12.99 ± 0.23a |
21 | mesityl oxide | - | 141-79-7 | * | -/- | 1.91 ± 0.01c | 2.13 ± 0.26c | 3.51 ± 0.42b | 3.56 ± 0.12b | 4.66 ± 0.22a |
58 | 2-amylfuran | - | 3777-69-3 | ** | 987/986 | 4.36 ± 0.73d | 5.08 ± 0.59cd | 6.25 ± 0.95bc | 6.81 ± 0.6b | 13.88 ± 0.47a |
67 | D-limonene | - | 5989-27-5 | ** | 1025/1025 | 1.45 ± 0.24c | 2.1 ± 0.29c | 2.87 ± 0.49b | 3.27 ± 0.45b | 8.24 ± 0.26a |
3 | methyl acetate | ∨ | 79-20-9 | * | -/- | 34.81 ± 0.51b | 19.78 ± 1.49c | 16.92 ± 1.15d | 17.24 ± 1.6d | 77.83 ± 0.28a |
4 | dimethyl sulfide | ∨ | 75-18-3 | ** | -/- | 35.76 ± 1.67b | 21.13 ± 2.02c | 20.64 ± 0.81c | 21.92 ± 1.84c | 53.46 ± 0.38a |
56 | 6-methylhept-5-en-2-one | ∨ | 110-93-0 | ** | 983/982 | 4.93 ± 0.46b | 4.59 ± 0.21bc | 4.09 ± 0.41c | 4.07 ± 0.19c | 5.6 ± 0.3a |
72 | (Z)-β-ocimene | ∨ | 13877-91-3 | ** | 1044/1044 | 9.45 ± 1.17b | 7.58 ± 0.51c | 6.78 ± 0.63c | 7.18 ± 0.3c | 17.72 ± 0.52a |
18 | toluene | * | 108-88-3 | ** | -/773 | 7.16 ± 0.38b | 6.49 ± 0.66bc | 5.65 ± 1c | 6.06 ± 0.25bc | 37.22 ± 0.99a |
10 | 2-methylbutanal | 0 | 96-17-3 | ** | -/665 | 21.14 ± 1.72c | 17.13 ± 1.09d | 23.13 ± 1.86bc | 25.97 ± 1.47a | 25.14 ± 0.62ab |
11 | 1-penten-3-ol | 0 | 616-25-1 | * | -/681 | 21.38 ± 1.2d | 39.15 ± 1.51c | 46.31 ± 1.12a | 43.72 ± 1.46b | 39.44 ± 0.18c |
44 | unknown-4 | 0 | - | - | 928/- | 0.27 ± 0.02bc | 0.23 ± 0.02c | 0.63 ± 0.01a | 0.31 ± 0.03b | 0.64 ± 0.05a |
86 | hotrienol | 0 | 20053-88-7 | * | 1102/1104 | 3.52 ± 0.1b | 2.69 ± 0.25c | 5.46 ± 0.21a | 5.41 ± 0.54a | 0 ± 0d |
91 | benzyl cyanide | 0 | 140-29-4 | ** | 1136/1135 | 4.01 ± 0.28a | 3 ± 0.05c | 1.45 ± 0.12d | 1.53 ± 0.09d | 3.61 ± 0.11b |
Tea Sample Name | Number |
---|---|
special grade of Nongxiang Tieguanyin | K110 |
first grade of Nongxiang Tieguanyin | K101 |
second grade of Nongxiang Tieguanyin | K102 |
third grade of Nongxiang Tieguanyin | K103 |
fourth grade of Nongxiang Tieguanyin | K104 |
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Wang, W.; Jin, S.; Guo, Y. Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics. Molecules 2019, 24, 1707. https://doi.org/10.3390/molecules24091707
Wang W, Jin S, Guo Y. Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics. Molecules. 2019; 24(9):1707. https://doi.org/10.3390/molecules24091707
Chicago/Turabian StyleWang, Wei, Shan Jin, and Yaling Guo. 2019. "Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics" Molecules 24, no. 9: 1707. https://doi.org/10.3390/molecules24091707