Evaluation of physicochemical properties and in vitro starch digestion of noodles enriched with thermally assisted potassium carbonate treated sweet potato residue

Abstract

In this study, we investigated the effect of thermally assisted potassium carbonate treatment sweet potato residue (TAPC-SPR) and its addition (0%, 5%, 10% and 15%) on the texture, multi-scale structure (microstructure, crystalline structure, short-range ordered structure) and in vitro starch digestibility of the noodles. The results demonstrated that the ratio of total dietary fiber (TDF) (75.62%–87.25%) and pectin (19.36%–23.36%) were increased, and the particle size distribution (175.67 μm–47.42 μm) was decreased in TAPC-SPR than sweet potato residues (SPR). This study suggested that suitable TAPC-SPR (5% and 10%) contributed to improving the texture properties of noodles, containing hardness, springiness, chewiness and adhesiveness. Sensory evaluation showed that noodles with suitable TAPC-SPR (5% and 10%) had an overall sensory acceptability relative to control. In addition, the intermolecular hydrogen bond interaction, the structure order, V-type starch complex and dense structure were observed. These structural changes limit the interaction of amylase with starch, elevate the resistant starch (RS) content, and lower the predicted glycemic index (pGI).