Oligomerization and hydroxylation of green tea catechins by oxidative enzymes

Promotie

Oligomerization and hydroxylation of green tea catechins by oxidative enzymes

Promovendus ir. JW (Annewieke) Verloop
Promotor prof.dr.ir. H (Harry) Gruppen
Copromotor dr.ir. JP (Jean-Paul) Vincken
Organisatie Wageningen University, Laboratory of Food Chemistry
Datum

vr 3 juni 2016 16:00 tot 17:30

Locatie Auditorium, building number 362
Generaal Foulkesweg 1
362
6703 BG Wageningen
0317-483592

Title for non-professionals

From green tea to black tea with oxidative enzymes and catechins

Summary

In this research more insight is obtained in the chemical reactions occurring in fresh tea leaves during black tea production. The role of different oxidative enzymes and the different phenolics in tea leaves have to a certain extent been illuminated by using model systems of the separated tea compounds. It was found that two different enzymes, polyphenol oxidase and peroxidase, are responsible for, respectively, the first step in the oxidation and for a hydroxylation reaction, the latter of which is expected to be of influence on the bitterness. This knowledge might be used in the future to control the process of black tea production. Black teas enriched in certain phenolics and teas with a desired brown hue and bitter intensity might be designed by controlling the enzymatic activity.