Effect of green tea flavonoids on Maillard browning in UHT milk

The ability of green tea flavonoids to control Maillard browning was investigated. Epicatechin (EC) and epigallocatechin gallate (EGCG) were added at levels of 0.1 and 1.0mmol/l to a glucose/glycine model system as well as into milk that was then thermally processed in a Microthermics processing system. Samples were assessed with (1) front-face fluorescence spectroscopy for Maillard browning, (2) Hunter L*, a*, and b*; and (3) sensory analysis. In the model gluocose/glycine system, EC and EGCG reduced Maillard fluorescence at the 0.1 mmol/l level, while fluorescence was negligible with added flavonoids at 1.0 mmol/l. When these flavonoids were added to milk, they reduced the production of Maillard. associated fluorescence with UHT processing. EC and EGCG also reduced the AE (Total color difference) during thermal processing. Throughout shelf-life testing, these compounds reduced Maillard associated fluorescence in milk. Milk samples processed with these extracts were monitored by sensory analysis during extended storage. The sensory evaluation found the green tea milk samples to be of similar liking to the control milk. These flavonoids may be of use to the food industry to control Maillard browning. (C) 2006 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.