Effects of gamma irradiation on antioxidant activities and chemical properties in Agaricus bisporus mushrooms

Agaricus bisporus is easily perishable and subject to microbial contamination. The present study aspires to follow antioxidant activities and chemical changes of Agaricus bisporus after being exposed to gamma radiation. Powder samples were irradiated at 2.5, 5, 7.5 and 10 kGy. Subsequently, antioxidant activities, total protein content and total soluble polysaccharide content of irradiated samples were evaluated. Result showed that gamma irradiation up to 10 kGy did not significantly affect antioxidant activities. 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity assay (DPPH) of non-irradiated and irradiated samples ranged from 2.07 +/- 0.09 to 2.19 +/- 0.14 mgAAE/g, whereas ferric reducing antioxidant power (FRAP) of irradiated samples varied from 32.74 +/- 0.39 to 34.52 +/- 1.45 mu mol FeSO4/g. Total phenolic contents were between 7.24 +/- 0.38 and 7.65 +/- 0.53 mgGAE/g. In terms of chemical properties, gamma radiation at 10 kGy showed no significant differences in total protein content and total water soluble polysaccharide content. Total protein contents were found from 42.46 +/- 0.28 to 43.18 +/- 0.13 %w/w. Amount of total water soluble polysaccharide content in non-irradiated and irradiated samples varied from 5.49 +/- 0.15 to 5.72 +/- 0.14 %w/w.