Effect of shaking process on correlations between catechins and volatiles in oolong tea

Publication date: Available online 12 April 2016 Source:Journal of Food and Drug Analysis Author(s): Shu-Yen Lin, Li-Chiao Lo, Iou-Zen Chen, Po-An Chen Shaking the tea leaves is the key manipulation to making oolong tea. It contributes to the formation of flavor and fragrance in oolong tea. The dynamic variations of catechins and volatile organic compounds (VOCs) during the shaking process were investigated. The results showed that the contents of epicatechin, epigallocatechin, epicatechin gallate (ECG), and epigallocatechin gallate first decreased after the shaking and then increased to the initial value before the next shaking. Geraniol, linalool and its oxides, and phenylethyl alcohol showed similar variations. The contents of trans-β-ocimene, 1H-indole, α-farnesene, and 3-hexenyl hexanoate increased after the second or third shaking in the late fermentation stage. However, the contents of aldehydes showed an opposite trend to other VOCs. The variations of ECG, epigallocatechin gallate, and phenylethyl alcohol had positive relationships, whereas those of ECG and cis-3-hexenal had negative relationships. The correlations between catechin and VOCs indicated that shaking affected the chemical transformation of the compounds in oolong tea. Graphical abstract
Source: Journal of Food and Drug Analysis - Category: Food Science Source Type: research