Improving delayed-release potential of winged bean starch by acetylation

Abstract

Winged bean starch was acetylated for evaluation of its effects on the physicochemical and release properties of starch. The modification was carried out with 0.8, 1.6, and 2.4 g of acetic anhydride. The degree of substitution (DS) increases proportionally from 3.85±0.2 to 5.37±0.09 with the increase in acetic anhydride concentration. The acetylation of winged bean starch increased swelling and solubility power with the transition of temperatures. The result showed that both amylose content (2.69±0.82%-2.92±0.84%) and water holding capacity (102.87±0.02-106.70±0.04) increased proportionally with the increase in acetic anhydride concentration. In vitro dissolution study was performed in USP type II apparatus using pH 1.2 and 6.8 as dissolution media. The formulations prepared with acetylated starches especially AS1 showed drug release of 68.92±0.22% in 2 h compared to 78.32±0.51–91.03±0.66% release in native starch formulations in that same period indicating improved delayed release property of acetylated winged bean starch.