Studies on the Storage of Plucked tea Leaves (Part 4)

Abstract

Ascorbic acid in plucked tea leaves was decomposed via dehydroascorbic acid and dike-toglonic acid during storage.The decomposition of ascorbic acid was more vigorous in injured leaves or in stored leaves at room temperature than in uninjured ones or in stored ones at 5°C.The, concentration of ascorbic acid in tea leaves decreased to about 40 to 22% after one day's storage at 15 and 25°C, respectively. But in stored leaves at 5°C, about 40% of initial concentration was remained after 8 days' storage.The decomposition of ascorbic acid in stored leaves was depressed dy infiltration of sugar through the stem' of tea leaves, therefore, it was thought that the decomposition of ascorbic acid was parallel to the decreasing of sugar concentration in stored leaves.In defrosted tea leaves, the decomposition of ascorbic acid and the activation of polyphenol oxidase were observed.In an atmosphere of high CO2 concentration, the decomposition of ascorbic acid in stored leaves was suppressed. But if this stored leaves was transferred into air, the oxidative decomposition of it was accelerated.