Applied Food Research (Dec 2021)
Effect of low dose γ-irradiation on the structural and functional properties, and in vitro digestibility of ultrasonicated stem starch from Corypha umbraculifera L.
Abstract
In the present study, non-conventional talipot starch was subjected to single and dual modifications using two non-thermal techniques; ultrasonication and γ-irradiation (1 kGy and 10 kGy). Free radical-mediated low dose γ-irradiation made remarkable changes in the morphological, physicochemical, and functional properties of ultrasonicated talipot starches compared to single modifications. Dual (ultrasonication+γ-irradiation) modification created deep grooves, reduced relative crystallinity and peak intensity of OH and CH2 groups by cavitation and radiolysis. Compared to ultrasonicated and γ-irradiated starches, dual-modified starches showed significantly reduced (p ≤ 0.05) pH, amylose content, and swelling power, and improved storage stability by lowering the retrogradation tendency. The in vitro digestibility of dual-modified talipot starches was increased by the enhanced action of digestive enzymes with starch. The gelatinization, pasting, and rheological properties significantly decreased (p ≤ 0.05) with the increasing dose of γ-irradiation in dual-modified talipot starches and represented soft gel possessing shear-thinning stability.