Physicochemical and structural evaluation of alkali extracted chickpea starch as affected by γ-irradiation

Abstract

In this study, starch isolated from chickpea was exposed to gamma-irradiation at 0, 4, 8 and 12kGy doses. The irradiated starches were evaluated for their physicochemical, morphological and pasting properties. The results revealed significant (p≤0.05) reduction in apparent amylose content, swelling power, turbidity, syneresis, L (lightness) value, and pasting parameters whereas solubility and b (yellowness) value increased with increase in irradiation dose. X-ray diffraction showed C-type of crystallographic pattern. Relative crystallinity (RC) of irradiated starches was different at different irradiation doses. Prominent changes were recorded in the FT-IR spectra of irradiated starch samples with respect to intensity and shifting of major bands in specific regions. Analysis of O − H and C − H stretches, bending mode of water and glycoside bonds of irradiated starches revealed marked decrease in their absorbance intensities. Scanning electron microscopy revealed cracking and clumping of starch granules at elevated doses of gamma-irradiation. Radiation doses were negatively correlated to swelling power, pasting parameters (peak viscosity, hold viscosity, final viscosity, setback viscosity and pasting temperature), turbidity, syneresis and apparent amylose content except solubility.