Glutathione suppresses the enzymatic and non-enzymatic browning in grape juice.

Browning tends to occur in grape juice during processing and storage and decreases the commercial value of it. Thus, browning inhibition is an important objective for manufacturers. This study aims to investigate the efficacy of glutathione as a browning inhibitor for use on grape juice. Grape juice browning treated with glutathione was monitored during processing and accelerated browning. 0.04% of glutathione inhibited 99.4% of the polyphenoloxidase activity in the grape juice. Consequently, during processing at room temperature and accelerated browning at 80 °C, the browning in the grape juice treated with glutathione was significantly lower than that in the control (p<0.05). The results indicate that glutathione is a promising browning inhibitor used in grape juice.