Determination of color parameters of gamma irradiated fresh and dried mushrooms during storage

Abstract

The visual appearance of mushrooms is one of the first quality determinants made by the Ghanaian consumer. Color parameters were measured for fresh mushrooms (Pleurotus ostreatus) irradiated at 0, 1, 2 and 3 kGy at a dose rate of 1.7 kGy hr-1 after harvest (0 day) and then measured after storage (5 days). Dried mushrooms were exposed to gamma radiation at 0, 0.5, 1, 1.5 and 2kGy at the same dose rate and stored in polythene and polypropylene packaging materials and stored for a period of 12 months. The effect of gamma radiation on colour was monitored at 0, 3, 6 and 12 months. The colour parameters for the colour change were quantified by the Hunter L (whiteness/darkness), a (redness/greenness) and b yellowness/blueness) system. These values were also used for calculation of the total colour change (ΔE), chroma (C), hue angle (H) and browning index (B.I). There were significant differences (P< 0.05) for L*, a*, b*, chroma, hue angle, browning index and overall colour change of fresh and dried mushrooms over the storage periods. There was an increase in a*-values while L*, b*, C and H values decreased. This study investigates the effect of ionizing radiations on the colour quality of oyster mushrooms during storage showing its suitability of usage in food preservation