Effects of Co‐Addition of Plant Peptides and Lauric Acid on the Physicochemical Properties and In Vitro Digestibility of Sweet Potato Starch

Abstract

AbstractThe effects of co‐addition of three plant peptides (P)—soybean peptide (SP), wheat peptide (WP) or corn peptide (CP), and lauric acid (LA)—on the physicochemical properties and in vitro digestibility of sweet potato starch (SPS) are investigated. The enthalpy (ΔH2), complex index (CI), ordered crystalline structure, and resistant starch (RS) content of the SPS–LA–P ternary system significantly increase, compared to those of the SPS–P and SPS–LA binary systems. The microscopic surface is smoother and denser, and the cross‐sectional gel layer is thicker. The peak viscosity, breakdown value, paste clarity, and gel hardness of the ternary system also significantly decrease, likely due to the formation of more SPS–LA binary complexes and SPS–LA–P ternary complexes in the ternary systems. The co‐addition of WP and LA demonstrates the most significant increase in the ΔH2 (1.48 J g−1), CI (48.74%), relative crystallinity (18.17%), and molecular orderliness of SPS–control, which also has reduced paste clarity (23.93%). The addition of SP and LA is most effective in reducing the peak viscosity (4183.33 cP) and gel hardness (221.72 g) of SPS, and the ternary systems containing WP and CP have the highest RS content of 29.81% and 28.74%, respectively.