Comparison of Starch Characteristics from Pigmented and Non‐Pigmented Sorghum Cultivars before and after Electron Beam Irradiation

Abstract

Abstract Starch is extracted from the seeds of a pigmented (Phule Rohini) and a non‐pigmented (Phule Maldandi) Indian sorghum cultivar using same wet milling method for both cultivars. This study is focused on investigation of the effect of the pigment on starch characteristics. Isolated starches differing in color are irradiated with an electron beam dose of 5 kGy and compared by measuring physicochemical, structural, pasting, and digestibility properties. Amylose content increases after irradiation and the increase is greater in the case of Phule Maldandi starch. The pigmented starch shows higher carboxyl content after irradiation which may be due to higher amylopectin content. Granular morphology remains constant after irradiation. Irradiation causes a decrease in swelling power and an increase in pasting viscosity of both starches. Color content of red sorghum starch is not changed significantly after irradiation. The increase in pasting viscosity and solubility of non‐pigmented starch is more drastic in nonpigmented starch than in pigmented starch after irradiation. Resistant starch decreases after irradiation which indicates opening up of granular structure or hydrolytic action of irradiation. Pigmented starch can have potential applications in custard powder and bakery products.