Gamma radiation technological feasibility of increasing shelf-life of table grapes

Gamma radiation (1 and 2 kGy) and different sources of sulfur dioxide (0.25% SO2, 4 g K2S2O5 + 4 g C6H8O7 per kg grape) and moist air heat (55 deg. C for 15 minutes) were used to increase shelf-life of Black Alicante table grapes stored at 10 deg. C and 95% relative humidity. The grape clusters were placed on foam polystyrene trays and packed with polyvinyl-chloride film. Gamma radiation at 2 kGy completely prevented decay of Black Alicante table grapes stored for 40 days at 10 deg. C without any discernible change in the organoleptic attributes of the berries. Moist air heat, 0.25% SO2 and 1 kGy gamma radiation used alone neither prevented nor delayed moulding, whereas potassium meta-bisulfite mixed or not mixed with citric acid delayed moulding for 15 and 35 days, respectively. 1 kGy gamma radiation dose in combination with 0.25% SO2 controlled moulding for the entire storage period of 40 days. Potassium meta-bisulfite mixed with citric acid or in combination with 2 kGy induced adverse organoleptic changes in the berries. (author)