EVALUATION OF OXIDATIVE STRESS AND ANTIOXIDATIVE SYSTEM IN BER (ZIZIPHUS MAURITIANA L.) FRUITS DURING STORAGE

Lipid peroxidation, oxidative stress and antioxidative system were monitored during storage of Ber fruits cv Umran (shelf life; 8-9 days) and Kaithali (shelf life; 4-5 days). Mature green fruits stored under ambient conditions were analyzedat a 2-day interval until complete deterioration. Throughout storage, lipoxygenase activity, malondialdehyde and hydrogen peroxide content were higher in Kaithali than in Umran and increased continuously in both the varieties. Activities of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase decreased continuously whereas that of peroxidase increased up to 4th day of storage and thereafter decreased. Umran showed higher activities of superoxide dismutase, peroxidase, ascorbate peroxidase and glutathione reductase at almost all the stages of storage. The catalase activity, however, was higher in fresh Kaithali fruits and thereafter differences among the varieties were insignificant. Ascorbic acid increased up to the 8th day of storage and then decreased sharply. Glutathione and beta-carotene exhibited a continuous decline whereas alpha-tocopherol first increased up to 4 days and then declined in both the varieties throughout storage.