Effect Of Heat Treatment On Structure Of Resistant Starch And Related Functions

Resistant starch (Resistant starch, RS) not only has the similar physiological function with dietary fiber. As a functional carbohydrate for improving body health, the prevention of major diseases has profound physiological effect. However, the different structure of RS in intestinal digestion in the mode and fermentation metabolism is different, then on intestinal physiology environment function is different. Starch generally absorbed from foods after heat processing which provided the premise for the further formation of RS. Understanding the effect of different heat treatment brings to the structure of RS, which will raise the RS biological benefits more manageable.This paper uses high amylose corn starch HylonTMⅥ as raw material with different heat treatment, and then by in vitro digestion, to obtain different types of RS:RS2, dry RS and hot press RS3. And then research on the structural characteristics of the RS using SEM, FTIR, XRD, HPLC.The digestion of RS showed a rapid digestion before 3h and slow metabolism after 3h. The final RS2 and dry heat RS are spherical particles with different proportion of amylopectin/HMW and plenty of LMW, while the hot press RS3 only contains LMW and shows irregular pieces. LMW is the mainly composition of each RS. Positive correlation between moisture content during heat treatment and the damage degree of starch structure, which determines the particle morphology, crystallization characteristics of RS. XRD and FTIR show that the crystallinity and degree of order of dry heat RS is the lowest, hot press RS3 instead.In vitro fermentation environment, three kinds of RS can significantly reduce the fermentation environment pH, no effect on the proliferation of Lactobacillus, while the butyricacid producing bacteria showed proliferation, and the quantity of butyric acid bacteria in fermentation liquid is proportional to the concentration of butyrate. Hot press RS3 can proliferate Bifidobacterium and E. Coli; RS2 can proliferate E. Coli; dry RS didn’t has proliferation effect on the two kinds of bacteria, while has most notably proliferation effect on the butyrate producing bacteria. Considering the pH, total Short-chain fatty acid (Short-chain fatty acid, SCFA), butyricacid and the amount of butyrate producing bacteria, this study screens out that dry heat treatment has the best effect.Using streptozotocin (STZ) induced type II diabetes model, and then the study found that diabetes increases intestinal microbiota abundance and diversity. The RS have the efficacy to improve the diabetic rat intestinal flora imbalance. In phylum level, the potentially harmful bacteria that associated with diabetes incidence is Proteobacteria, while Bacteroidetes is the superiority strain. Dry heat treated RS has the best comprehensive control effect. In genus level, the harmful bacteria related with diabetes is E. coli. RS2 and dry RS have the best control effect.