Moisture mediated effects of γ-irradiation on physicochemical, functional, and antioxidant properties of pigmented brown rice (Oryza sativa L.) flour

Flours obtained from pigmented brown rice were conditioned to moisture contents of 10 and 12% and then subject to irradiation at 0, 2.5 and 5 kGy doses. Effect of irradiation on the physicochemical, functional and antioxidant properties of rice flour samples was evaluated. Moisture, protein, fat, ash and carbohydrate content of native (unirradiated) flour were 11.5, 5.66, 3.16, 1.16 and 78.52 g/100 g, respectively. Apparent amylose content was observed to decrease significantly (p ≤ 0.05) with the increase in moisture content and irradiation in the flour. Water and oil absorption capacities increased non-significantly (p ≥ 0.05) upon irradiation whereas foaming capacity and stability in general were found to decrease on irradiation. Peak, trough setback and final viscosity decreased on irradiation. Irradiation led to an overall increase in the total phenolic content and antioxidant activity except for the flour irradiated with 2.5 kGy dose having a moisture content of 10%.