Effects of gamma irradiation on starch granule structure and physicochemical properties of brown rice starch

In the present research effects of gamma irradiation (5-20 kGy) on the physicochemical, antioxidant and thermal properties of brown rice starch were studied. Scanning electron microscopy displayed mostly polyhedral shapes with no surface fractures. XRD displayed characteristic A type pattern and decrease in per cent crystallinity (22.53-20.41%) was observed as the dose increased from 5 to 20 kGy. DPPH % inhibition and FRAP values were increased in a dose dependent manner. Pasting properties (peak, final and setback viscosity) decreased with irradiation. Pasting temperature also significantly decreased with irradiation for all the irradiated starches. The transition temperatures, enthalpy of gelatinization, pH and apparent amylose content of starch decreased significantly with increase in irradiation dose.