| Resistant starch has beneficial effect to regulate postprandial blood glucose, and improves glucose and lipid metabolism disorders. However, researches have shown that this is not a continuing effect. The paper chose four different physical and chemical properties of starch to prepare high resistance RS3, and digestibility was explored. Filtering out corn resistant starch, pueraria resistant starch, mung bean resistant starch, to perform a long-term animal experiment, observed and compared blood glucose, hepatic glycogen and intestinal environment, such as incretin and changes of SCFA, in order to find out the mechanism of biological adaptive and try to control it.Using debranched and cycled retrogration method to prepared high resistant starch, and compared amylose content, crystal structure and thermal properties. The results showed that resistant starch amylose content is higher than native starch, both corn starch and mung bean starch were A-type starch, potato starch and potato resistant starch were B-type crystals, pueraria starch was type C-type crystal, corn resistant starch, Pueraria resistant starch and mung bean resistant starch were B+V type starch. After retrogration, gelatinization temperature and tempertature range, gelatinization enthalpy △H were increased.To prepare resistant starch by pullulanase, and established digestion kinetic model compared with native starch. Digestion of resistant starch through different time was investigated by X-ray diffraction, Differential scanning calorimetry, Fourier transform infrared. The results showed that corn starch performed a better digestive progress, and hydrolysis rate constant was 2.32h4, which is higher than mung bean resistant starch (1.99h-1). The hydrolysis rate constant of corn resistant starch was minimum (1.13 h-1). The areas under the curve have significantly different between before and after 2 hours of native starch and resistant starch, which showed that process of resistant starch digestion is a steady glucose release state and glucose was slowly and persistently absorbed. Both crystallinity and enthalpy of digesta were increased after 2 hours, which showed that proceed mainly was hydrolysis kinetic. After 2h, crystallinity decreased but showed a disordered change process, amylose was rearrangement and linked by hydrogen bond, the formed polymer can resist amylase hydrolysis. The digestion showed a competition between the kinetics of enzyme hydrolysis and the kinetics of amylose retrogradation. However, as short-chain amyloses were continuously hydrolyzed by pancreatin in the small intestine, the equilibrium moved to the hydrolysis of resistant starch, which may result in adaptive phenomenon.SD rats were fed on a diet enriched with fat and glucose, after 4 weeks, rats were injected intraperitoneally with a low dose STZ twice (35mg/kg once a week) to establish type Ⅱ diabetes model, then take corn resistant starch, pueraria resistant starch and mung bean resistant starch as diets to research long-term effects in diabetic rats, after weeks, change resistant starch species, and compared with original resistant starch group. The result showed that fed resistant starch for weeks, blood glucose were significantly lower than diabetes rats, P<0.01. After 14 weeks, corn resistant starch group decreased by 23.5%, pueraria resistant starch group decreased by 23.2%, mung bean resistant starch group decreased by 28.5%. After 19 weeks, compared each resistant starch groups, corn resistant starch group which converted for mung bean resistant starch reduced 17.63% than original corn resistant starch group,between pueraria resistant group reduced 14.65%, P<0.05; mung bean resistant starch group have no significant difference, and two groups maintain with a stable blood glucose. Compared with physical indicators, AUC of glucose tolerance have significant difference among corn resistant starch groups and among pueraria resistant starch groups, P<0.05, mung bean resistant starch group have no significant difference (P>0.05), and AUC of three resistant starch groups were lower than control group, but higher than metformin group. Glycohemoglobin levels among corn resistant starch groups and among pueraria resistant starch groups were significantly difference, P<0.05; among mung bean resistant starch groups have no significant difference, P>0.05. Hepatic glycogen content among corn resistant starch group and among pueraria resistant starch groups have extremely significant difference, P<0.01, among mung bean resistant starch groups difference are not significant. GLP-1 content at 19 week were significant difference among corn resistant starch groups, pueraria resistant starch groups and mung beans resistant starch groups, P<0.01, and the changed group were higher than the original resistant starch group. The content of SCFA in colon also have significant difference, such as propionic acid content in corn resistant starch groups, P<0.01, and butyric acid content has a significant difference in three groups, P<0.01.In vitro fermentation experiments within 24 hours showed that content of acid production varies considerably, Biological Adaptive may due to the changes of intestinal flora environment, that adaptability to single resistant starch in a long-term period, and SCFA produced by different resistant starch have a stress reaction on intestinal glucose absorption and incretin secretion of the pancreatic hormone. |
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