Understanding synchronous regulating effects of starch-protein interactions on starch digestion and retrogradation under thermal shear processing

Although starch-protein interactions have been widely used to regulate starch digestibility and retrogradation during food processings, their synchronous regulating effects on both properties still remain largely unexplored. The effects of interactions with pea protein (PP) under thermal shear processing on the digestion and retrogradation properties of modified chestnut starch were investigated. Results show that thermal shear processing broke starch multi-scale structure, leading to the reduction in molar mass, short-range ordered structure, crystallinity, and starch compactness, in turn increasing starch digestibility and accelerating starch retrogradation. However, PP molecules would interact with chestnut starch through hydrogen bonding to form the starch-protein complexes during thermal shear processing, which caused an increased resistant starch. These starch-protein interactions also inhibited the formation of short-range, long-range ordered structure, aggregate structure during storage, causing a reduced degree of retrogradation. The results provided new insights into the synchronously regulating effects of starch-protein interactions under thermal shear processing on starch digestion and retrogradation, which would facilitate the development of starch-based foods with high nutrition and quality.