Please use this identifier to cite or link to this item:
Title: Kinetic study of the thermal stability of tea catechins in aqueous systems using a microwave reactor
Authors: Wang, R.
Zhou, W. 
Wen, R.-A.H.
Keywords: Degradation
Kinetic model
Tea catechins
Thermal stability
Issue Date: 9-Aug-2006
Citation: Wang, R., Zhou, W., Wen, R.-A.H. (2006-08-09). Kinetic study of the thermal stability of tea catechins in aqueous systems using a microwave reactor. Journal of Agricultural and Food Chemistry 54 (16) : 5924-5932. ScholarBank@NUS Repository.
Abstract: Tea catechins may undergo complex reactions such as oxidation, polymerization, and epimerization during thermal processing. The thermal stability of tea catechins in an aqueous system, including degradation and epimerization reactions, was investigated using a microwave reactor. Reactions were controlled at high temperatures ranging from 100 to 165°C with various durations up to 120 min. Three sources of tea catechins containing different levels of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), and their epimers were studied. Kinetic models for the degradation/ epimerization of tea catechins were developed and validated by the reactions at 145°C. It was shown that the epimerization and degradation of tea catechins followed first-order reactions and the rate constants of reaction kinetics followed the Arrhenius equation. Values of the activation energy (Ea) for the epimerization of EGCG from epi- to nonepi-structures, the epimerization of GCG from nonepito epi-structures, and the total degradation of EGCG and its epimer GCG were 117.6, 84.2, and 42.8 kJ/mol, respectively. For ECG and CG, the Ea values were 119.3, 96.2, and 41.6 kJ/mol, respectively. The mathematical models may provide a useful prediction for the loss of tea catechins during any thermal processing. © 2006 American Chemical Society.
Source Title: Journal of Agricultural and Food Chemistry
ISSN: 00218561
DOI: 10.1021/jf0611419
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.


checked on Mar 12, 2019


checked on Mar 4, 2019

Page view(s)

checked on Dec 21, 2018

Google ScholarTM



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.