Abstract:

Decreasing SO2 residue and controlling the incidence of postharvest diseases are the key factors in reducing the
loss of table grapes during storage. ‘Munage’grapes were treated with SO2-ClO2 and SO2, and stored at 0 ℃. Effects of SO2-ClO2
and SO2 treatments on fruit SO2 residue and quality of grapes were investigated during storage. The results showed that
SO2-ClO2 treatment significantly reduced SO2 residue in ‘Munage’ grapes, resulting in a 10.24% decrease in the SO2 residue
level after 60 days of storage as compared to SO2 treatment. Moreover, SO2-ClO2 treatment inhibited the reduction in the
contents of nutrients (VC, soluble sugar, and TA), suppressed the accumulation of malondialdehyde (MDA) and reactive
oxygen metabolites (O2
-·and H2O2), maintained higher activities of phenylalanine ammonia-lyase (PAL), superoxide
dismutase (SOD) and peroxidase (POD), and effectively reduced appearance quality loss, decay incidence, fruit drop rate
and the increase of browning index respectively by 1.4%, 9.36%, 7.28%, and 3.41% after 60 days of storage as compared to
SO2 treatment. Fruit softening was also inhibited. In conclusion, SO2-ClO2 treatment can help improve the postharvest quality
and disease resistance of ‘Munage’grapes and delay fruit senescence during storage, indicating that SO2-ClO2 will have a
great potential for preservation of table grapes.

Key words: ‘Munage&rsquo, grapes, SO2-ClO2, SO2 residue, postharvest quality