Gamma-irradiation improves the color and antioxidant properties of Chaga mushroom (Inonotus obliquus) extract.

The objective of this study was to evaluate the effect of ionizing radiation on color and antioxidative properties of Chaga mushroom (Inonotus obliquus) extract (CME). CME (10 mg/mL) was gamma-irradiated at 0, 3, 5, 7, and 10 kGy, and color, antioxidant activity, and total phenolic compound levels were then determined. The lightness and yellowness were increased (P < .05), and the redness was decreased (P < .05), as irradiation dose increased. The antioxidant parameters such as the 2-diphenyl-1-picrylhydrazyl, superoxide, and hydroxyl radical scavenging activities, ferric reducing/antioxidant power, and inhibition of lipid peroxidation increased as the irradiation dose increased. Also, the total phenolic compound levels of CME were increased (P < .05) by gamma-irradiation. These results suggest that gamma-irradiation could be considered a means for improving the antioxidant properties and the color of CME.