Abstract:

This study aimed to investigate the quality characteristics of green tea processed from four albino/ etiolation tea tree varieties in Xinyang area, with the goal of analyzing the differences in quality features of these four types of green tea from the perspective of varieties. Four albino/ etiolation tea tree varieties were selected, and tea samples were prepared according to the traditional Xinyang Maojian tea processing method. Sensory evaluation and biochemical composition data were combined with multivariate analysis (PCA, OPLS-DA), revealing significant quality differences and key indicators attributable to the tea cultivar. The results showed that the sensory quality and +C (catechin) content of the ‘Zhonghuang No.1’ tea sample were superior to other three samples. The caffeine content of the ‘Baiye No.1’ tea sample was the lowest, while the tea polyphenols, amino acids, ECG (epi-catechin-3-gallate), and EGCG (epi-gallocatechin-3-gallate) content of the ‘Zhonghuang No.2’ tea sample were the highest. The water extractable substances, EC (epi-catechin), and EGC (epi-gallocatechin) content of the ‘Suyu Huang’ tea sample were the highest. Correlation analysis indicated that the sensory score of tea was positively correlated with free amino acids, caffeine, ECG, and ester catechins, and negatively correlated with EGC, EC, non-ester catechins, and total catechins (P<0.01). PCA extracted three principal components, and the comprehensive scores from high to low were ‘Zhonghuang No.2’> ‘Suyu Huang’> ‘Zhonghuang No.1’ > ‘Baiye No.1’. The established OPLS-DA model identified three key compounds that distinguished different varieties, namely tea polyphenols, EGC, and EGCG, which could clearly divide the four tea tree varieties into two categories, and the model was reliable. In summary, this study clarified the quality characteristics of green tea processed from four albino/ etiolation tea tree varieties in Xinyang area, providing a reference basis for the introduction direction of specific tea tree varieties.

Key words: Xinyang Maojian, albino tea, etiolation tea, quality components, catechin, amino acids, principal component analysis (PCA), sensory quality