Stilbene, as phyto-oestrogens, can construct resistant starch through noncovalent interactions with starch: A structural correlation study

Stilbenes are one of the major phytoestrogens with a variety of biological and nutritional functions, which have attracted attention in field of nutrition recent years. In this study, stilbenes with different molecular structure including resveratrol (RA), pterostilbene (PB) and polydatin (PD) were selected to interact and complex with rice starch under high pressure homogenization (UHPH), and the changes of multi-scale structure and digestibility of the complex were discussed. The results showed that the digestibility of starch substantially reduced after interacting with RA/PB/PD. When RA/PB/PD additions were 8%, the resistant starch (RS) content reached 36.3%, 33.4% and 23.8%, respectively. From the structural perspectives, on the one hand, RA/PB/PD could form inclusive complexes with starch via non-covalent bonds and further form stable V-type crystalline and relatively loose aggerate structure. On the other hand, RA/PB/PD could be partly released during digestion process from the loose region of the structure to inhibit α-amylase. Among them, RA with smaller molecular structure and more phenolic hydroxyl groups had the most pronounced modulatory effect. Overall, the results provided basic data for the rational design of rice starch-based foods with nutritional functions.