Impact of heat treatment and flavorings on the antioxidant capacity of black and green tea

Abstract

Thehighantioxidantcapacityofteaiswell-known,buttheeffectofflavoringslikehoneyorlemonhasbeenlessstudied. Their antioxidants can interact with each other, the global result being also affected by the brewing temperature. The combined effect of heat (55 and 80 8C) and flavorings (acacia and honeydew honeys, lemon juice) on the total polyphenol, total flavonoid content and antioxidant capacity of black and green teas was studied. In many cases higher antioxidant capacity was obtained at 80 8C. Teas flavored with honeydew honey had higher antioxidant capacity than those containing acacia honey. Addition of lemon decreased the antioxidant capacity of tea with honey. No synergies were confirmed in any of the compositions investigated. Vitamin C content of lemon-containing black tea was reduced by half at 80 8C compared to tea brewed at 55 8C; while honey was shown to partly prevent this loss of ascorbic acid.