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Article

Stability of Tea Catechins in the Breadmaking Process

Rong Wang and Weibiao Zhou*

Food Science and Technology Program, Department of Chemistry, National University of Singapore, Science Drive 4, Singapore 117543

J. Agric. Food Chem., 2004, 52 (26), pp 8224–8229

DOI: 10.1021/jf048655x

Publication Date (Web): December 8, 2004

Author to whom correspondence should be addressed [telephone (65) 6874 -3501; fax (65) 6775-7895; e-mail chmzwb@nus.edu.sg].

Abstract

A green tea extract (GTE) was incorporated into bread as a source of tea catechins. The stability of tea catechins in the breadmaking process including unfrozen and frozen dough was studied. A method was developed for the separation and quantification of tea catechins in GTE, dough, and bread samples using a RP-HPLC system. The separation system consisted of a C18 reversed-phase column, a gradient elution system of water/methanol and formic acid, and a photodiode array UV detector. Tea catechins were detected at 275 nm. GTEs at 50, 100, and 150 mg per 100 g of flour were formulated. The results obtained showed that green tea catechins were relatively stable in dough during freezing and frozen storage at −20 °C for up to 9 weeks. There were no further detectable losses of tea catechins in bread during a storage of 4 days at room temperature. It was also revealed that (−)-epigallocatechin gallate (EGCG) and (−)-epigallocatechin (EGC) were more susceptible to degradation than (−)-epicatechin gallate (ECG) and (−)-epicatechin (EC). (−)-EGCG and (−)-ECG were normally selected as the quality indices of green tea catechins, and their retention levels in freshly baked bread were ca. 83 and 91%, respectively. One piece of bread (53 g) containing 150 mg of GTE/100 g of flour will provide 28 mg of tea catechins, which is 35% of those infused from one green tea bag (2 g).