Preliminary post harvest treatments for improving shelf life of white button mushroom (Agaricus bisporus)

Agaricus bisporus (white button mushroom) is highly perishable and there is a need to devise economical and practical techniques which result in minimal colour and textural changes so as to extend the shelf life and allow easy transportation of harvested mushrooms to far off markets. In this study freshly harvested fruit bodies of A. bisporus strain U-3 were graded before subjecting them to different washing treatments [plain water, citric acid (0.5%), potassium metabisulphite (0.05%) or combinations of these washings with blanching (40 sec)] and observations were made on physical (color and texture) and biochemical (polyphenol oxidase enzyme) properties to elucidate the optimum preliminary treatment of these mushroom strains. There were significant differences in the overall color difference (?E) calculated on the basis of the L, a and b values and ?E was least for the treatment of blanching + CA+ KMS. Texture analysis showed that hardness decreased in all treatments where blanching of the mushroom strains had been done. Among these treatments, maximum hardness (1361.02 gm) was recorded in treatment T7 (Blanching + CA + KMS). The minimum PPO activities (0.036 U.min-1 gm-1) were observed in treatments T7 (Blanching + CA + KMS).