Changes of vitamin C and superoxide dismutase (SOD)-like activity of persimmon leaf tea by processing method and extraction condition

The persimmon leaf tea was produced from persimmon leaves by three different methods (conventional, steamed, fermented) and the changes of total vitamin C and superoxide dismutase(SOD)-like activity were investigated. The amount of total vitamin C was the highest in fermented persimmon leaf tea which was 47% of total vitamin C of raw persimmon leaves. The SOD-like activity of conventional and fermented persimmon leaf teas were a little higher than that of steamed. The total vitamin C of steamed persimmon leaf tea was decreased slowly as the extraction time was increased. That of fermented persimmon leaf tea was increased generally at , and increased until 5min and then decreased at , The optimum extraction condition of total vitamin C in fermented persimmon leaf tea was 3min and 5min at , 5min and 10min at . The total vitamin C of conventional persimmon leaf tea was so little that could not be measured by DNP method. The SOD-like activity of conventional and steamed persimmon leaf teas were increased and that of fermented showed the trend of increasing-decreasing-increasing. Fermented persimmon leaf tea had higher SOD-like activity than conventional and steamed at all tested conditions, and the optimum extraction condition of SOD-like activity was 3min and 10min at .