olyphenols from green and black teas show a pronounced oxygen consumption leading to autoxidation of compounds like epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate (Roginsky & Alegria, 2005). Similar behaviour is reported for autoxidation of tea catechins, which showed to be highly endothermic, so elevation of temperature stimulates oxidation reactions (Roginsky and Alegria, 2005 and Roginsky and Barsukova, 2000).