Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch

Abstract

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3–12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G’ and G’’ values for crosslinking starch samples varied from 3086.00–5507.50 Pa and 513.92–800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.