Repeating treatment of anaerobic and aerobic incubation increases the amount of #gamma#-Aminobutyric acid in tea shoots

摘要

#gamma#-Aminobutyric acid (GABA), a hypotensive compound, is formed from glutamic acid by glutamate decarboxylase under anaerobic conditions in tea shoots. In the first three hours of anaerobic incubation; glutamate was remarkably decreased and GABA was considerably increased. But under continuous anaerobic incubation, those of amino acids remained almost constant. After three hours of anaerobic incubation, when tea leaves were placed under aerobic condition, glutamate increased rapidly up to its original amount. But GABA didn't decrease. After one hour of aerobic incubation, tea leaves were given three hours of anaerobic incubation again, and then accumulated glutamate changed to GABA. As a result of this treatment, the amount of formed GABA increased over 1.5 times more than that under usual continuous anaerobic incubation. By four times repetition, GABA in tea leaves was formed 2.3 times as much as that under usual anaerobic incubation in the third crop of tea. By this new method, the level of GABA in tea leaves of the third crop reached to the same level as tea leaves of the first crop treated by the previous method.