Alternatives to sulfur dioxide to maintain quality of table grapes, including various combinations of rachis removal, chlorinated wash, hot water treatment, and modified atmosphere packaging, were explored in this study. Grapes were prepared by cutting off the rachis 1 to 2 mm from the fruit or by keeping the clusters intact. After initial preparation, short-stem and cluster grapes were subjected to chlorinated wash and/or hot water (45 °C, 8 min) treatment and packaged in plastic trays sealed with a gas-permeable film. The treated grapes as well as the commercially packed grapes (COM) in their original packages were stored at 5 °C for up to 4 weeks. Hot water treatment resulted in significantly (P < 0.05) higher oxygen retention and lower carbon dioxide accumulation in package headspaces, maintained a firmer texture, higher overall visual quality, lower decay rate, and lower microbial populations than other treatments or COM during the entire storage period. Grapes that were cut from the rachis and treated with hot water and chlorine maintained the highest quality for 4 weeks with the least decay among all treatments. A chlorine prewash treatment significantly (P < 0.05) reduced microbial populations on cluster grapes and maintained better overall quality. Conventional COM grapes developed dark decay and lost turgidity and were of unacceptable quality at 28 days of storage.
Hot Water Treatment in Combination with Rachis Removal and Modified Atmosphere Packaging Maintains Quality of Table Grapes
