Stability of tea catechins in the breadmaking process.
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 degrees 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 approximately 35% of those infused from one green tea bag (2 g).
Wang
Rong
R
Food Science and Technology Program, Department of Chemistry, National University of Singapore, Science Drive 4, 117543, Singapore.
Zhou
Weibiao
W
D001939:Bread; D028241:Camellia sinensis / Q000737:chemistry; D002392:Catechin / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003116:Color; D004355:Drug Stability; D005511:Food Handling / Q000379:methods*; D010936:Plant Extracts / Q000737:chemistry; D013662:Tea / Q000737:chemistry*
D010936:Plant Extracts; D013662:Tea; D002392:Catechin