Analysis of sensory evaluation and quality composition on“enzymatic overbrewing” treatment of Mengding yellow tea

Crude polyphenol oxidase enzyme liquid of fresh tea leaves was added to rolled leaves in Mengding yellow tea processing to make new process yellow tea.Method of sensory evaluation,quality composition determination and micro component detection were used to systematically analyze its quality characteristics.The results demonstrated that the “enzymatic overbrewing” yellow tea's color was brighter.Further more,its aroma was sweeter and tasted more mellow with “light fermentation” fragrant.Theaflavins(TFs)and thearubigins(TRs) was increased by 0.50 times and 0.10 times.However,tea polyphenols and total catechins were decreased moderately.While the total amino acids was increased slightly.As a result,the tea tasted bitter,more mellow and fresh.HPLC test results showed that the content of bitterness and astringency of ester catechin components EGCG and ECG were decreased by 12.86% and 6.19% to promote tea taste.GC—MS detection results showed that 30 kinds of new aroma components was founded in the enzymatic yellow tea.The amount of phytol with fermentation fragrant was detected 10.64%,which was 10.04 times the control.That showed that enzymatic light fermentation was caused by the “enzymatic overbrewing”,which will make the yellow tea produce characteristic color and flavor.At the same time,the “enzymatic overbrewing” processing of yellow tea can not only improved the quality of yellow tea,but also improved the processing efficiency about 2.8 times,which can promote the standardization and scale production of yellow tea.