Effect of γ-irradiation on granule structure and physicochemical properties of starch extracted from two types of potatoes grown in Jammu & Kashmir, India

•Functional properties of the starches changed with irradiation.•Scanning Electron Microscopy showed surface cracking of starch granules.•Relative crystallinity decreased while X-ray diffraction pattern remained unchanged.

In this study red and white potato starches were treated with γ-irradiation of 0, 5, 10 and 20 kGy. Physicochemical, pasting and morphological properties of the irradiated starches were investigated. Apparent amylose content, pH, moisture, swelling power and syneresis decreased; whereas carboxyl content, water absorption capacity and solubility increased with increasing irradiation dose. Pasting properties also decreased significantly (p ≤ 0.05) upon increasing the irradiation dose. Observation under scanning electron microscope (SEM) showed surface cracking of the starch granules by γ-irradiation which increased with increase in irradiation dose. X-ray diffraction pattern remained the same upon irradiation but a decrease in relative crystallinity was observed with increasing irradiation dose.