The Research On Taste Compounds Of Green Tea

Green tea is the largest output tea in our country, belonging to one of six major teas, unfermented tea, producing areas located in the tea production in the province, city, and autonomous regions, including Zhejiang, Anhui and Jiangxi provinces in the highest yield, the optimal quality in China. The natural substances have more retention in leaves of Green tea, and are the important factors of taste in infusions, and have been a hot research spot at home and abroad.This paper is mainly on the flavor compounds of green tea with qualitative and quantitative analysis, the taste sensory quality with the introduction of modern technology on sensory evaluation for quantitative evaluation, and the research on the relationship of flavor compounds of Green tea with the characteristics of taste. The results are as follows:1,Through analysis, the ranges of the main flavor components of green tea in accordance with the standards of brewing tea sensory evaluation: TP 104.16 mg/100mL to 173.27 mg/100mL; amino acids 19.58 mg/100mL to 61.14 mg/100mL; EGC, EGCG, EC, GCG and ECG respectively 407.68μmol/L to 763.91μmol/L, 111.91μmol/L to 165.98μmol/L, 971.61μmol/L to 1257.08μmol/L, 185.63μmol/L to 397.82μmol/L, 207.57μmol/L to 255.23μmol/L, 236.20μmol/L to 311.61μmol/L; Caffeine 1190.19μmol/L to 1543.10μmol/L; Flavonoid glycosides 1to 4, rutin and flavonoid glycosides 6 to 9 respectively 0.13mg/100mL to 1.09mg/100m L, 0.58mg/100mL to 2.27mg/100mL, 0.19mg/100mL to 2.53mg/100mL, 0.10mg/100mL to 2.32mg/100mL, 1.03mg/100mL to 2.09mg/100mL, 0.11mg/100mL to 3.91mg/100mL, 0.09mg/100mL to 4.63mg/100mL, 0.23mg/100mL to 1.61mg/100mL, 0.31mg/100mL to 3.30mg/100mL.2,With principal component analysis to the date of the main taste component in infusions, it resulted that the first four principal components could explain 94.98% of the total variation. The first four principal components represented the follow compounds: epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin, gallocatechin gallate, (+)-catechin and caffeine. These compounds are the characteristic compounds of Green tea from the point of relative contents.3,The comparison with the main taste ingredients in infusions of Green tea, 1,2 PCA sample map indicates that the samples are broadly divided into three categories : Category 1 includes samples A, B, C, O, T, V, W, X, Y, Z, e; Category 2 includes sample D, G, P, Q, R, S, a, b, d, f, g; Category 3 includes sample I, J, K, L, M, N, h, i. But 3, 4 PCA sample map has the distribution of more chaos, which has no visible separation characteristics.4,According to the results of quantitative analysis description of the sensory nature of infusions, using conversion Continental distance category average law - clustering, it could have 35 green tea samples into four categories. And category 1 has the strongest umami; Category 3 has the strongest bitter, slightly higher than category 4; Category 4 has the strongest astringency; as for category 2, it has not obvious characteristic taste.5,From the correlation analysis of the main taste ingredients and sensory nature in infusions of Green tea, we can learn: EGCG, EGC, ECG and Rutin is the important factor of bitter-astringency; Caffeine is the important factor of bitter; amino acid is the important factor of umami.6,According to the taste thresholds of catechin, establishing a formula on epigallocatechin gallate equivalent to the expression on the strength of astringency: TEGCGE(μmol/L)=C+190~* (A/520+B/410+D/930+E/390+F/260), A～F represent the contents of EGC, D-C,EGCG, EC, GCG, ECG And the formula can better express the correlation of catechins and astringency.