Sand frying-induced assembly of coix seeds starch with oils into stable structures: A comprehensive investigation based on starch-lipid interaction.

Abstract

Processing (Paozhi) is a pre-treatment step before the application of crude herbs in traditional Chinese medicine (TCM), which has been employed for centuries to regulating the functional properties of raw material. Current work aims at exploring how paozhi treatment tailors the composite behavior and physicochemical properties of coix seed starch-oils mixtures system, through inspecting the interactions between starch and oils under simulated sand frying conditions. The results indicate that processing induces significant morphological changes, leading to the formation of a porous starch-like structure. During this process, oils interact with starch molecules, facilitating the reorganization of the starch matrix and the formation of starch-lipid complexes (V-type inclusion complexes) as well as starch-lipid aggregates (oil is physically trapped). These structural changes, in conjunction with the interactions between water and oil, enhance the gelatinization properties and promote the slowly digestible characteristics of the sand-fried coix seed system, resulting in a gradual release of oil components. This study provides a foundation for further investigation into the mechanisms underlying the processing of starch-rich medicinal and food crops and their implications for health and nutrition.