Quality Changes in Oyster Mushrooms during Modified Atmosphere Storage as Affected by Temperatures and Packaging Materials

摘要

Modified atmosphere packaging was applied to oyster mushrooms (Pleurotus ostreatus) to study the effect of storage temperatures and packaging materials. Whole mushrooms (200 g) were packaged with polyethylene film (PE, 60 mu m thickness), ethylene vinyl acetate (EVA), or ceramic film (containing 5% zeolite) and stored at 0, 5, 10 and 20 deg C. Weight loss, color, firmness, gas composition (O_2, CO_2) inside the film package and ethanol content in the tissue of MA packaged mushrooms were examined. Mushrooms that were packed unwrapped in a conventional hardboard box (2 kg) lost marketability at a very early stage of storage due to weight loss, shrinkage, browning, and spore formation. During storage, film packaging prevented or retarded the deterioration of the mushrooms in the aspects of appearance, texture, and discoloration. Firmness slightly decreased with storage time. Total color difference was much higher in the control than in the film-packaged mushrooms and rapidly increased at the early ofstorage. Correlation analysis showed a high correlation between total color difference and b values. These results were characterized by the reduced respiration rate resulting from elevated carbon dioxide and reduced oxygen levels in the package. At allstorage temperatures, ethanol content in the tissue increased slightly at the early part of storage and rose considerably towards the end of the storage period. Ethanol content in the oyster mushrooms was higher in the stipe than in pileus tissues. Theshelf life of the oyster mushrooms was about 8 approx 11 days at 0 deg C, about 4 approx 6 days at 5 deg C, about 2 approx 3 days at 10 deg C, and about 1 approx 2 days at 20 deg C.