Effect of gamma irradiation on physicochemical properties of broad bean (Vicia faba L.) starch

Starch isolated from broad beans (Vicia faba L), was treated by gamma irradiation at 0, 5, 10 and 15 kGy doses. Moisture, protein, fat and ash contents of unirradiated (0 kGy) starch were found to be 79.1 g/kg, 5.0 g/kg, 4.7 g/kg and 4.8 g/kg, respectively. Effect of irradiation on physico-chemical properties of native starch was studied. The results revealed significant (p <= 0.05) increase in solubility, carboxyl content, water absorption capacity and freeze thaw stability with the increase in irradiation dose, whereas pasting properties, syneresis and pH were reduced significantly following irradiation treatment. X-ray diffraction pattern showed C type of pattern in native as well as irradiated starches, with reduced intensity of peaks in irradiated starches. Granule morphology under scanning electron microscopy revealed that granules were round, oval, irregular or elliptical. Granules varied in length from 6.8 to 14.9 mu m and in width from 3.1 to 10.5 mu m. Pearson co-relation studies revealed that irradiation dose was positively co-related with water absorption capacity, solubility index and negatively correlated with syneresis, freeze thaw stability, swelling index, and pasting properties. (C) 2013 Elsevier Ltd. All rights reserved.