| People focus on chronic diseases such as diabetes,hyperlipoiedemia,hypertension and cardiovascular disease as the living standard rose.Traditional high-calorie and high-fat diet has been replaced by a healthy diet,therefore,the development of low-calorie food is of great significance.Debranched starch has beneficial physiological functions,such as preventing intestinal diseases,lowering blood sugar and lipid,and it is similar to dietary fiber.Konjac glucomannan(KGM)is a thermoreversible gel with low-calorie and high-viscosity.In this study,a novel starch compound with good physicochemical properties and low-digestibility was composed by KGM and debranched corn starch,and the effects of different KGM concentrations on the properties of enzymatic modified corn starch were studied.Animal experiments have shown the effect of compound samples on diabetic mice through detecting blood glucose level,blood lipid level and viscera tissues.And the change of intestinal flora and metabolic product on diabetes mice was studied and explained the reducing mechanism of blood glucose,blood lipid of starch compound.(1)The optimum conditions of debranched corn starch(DCS)by pullulanase were determined by single-factor and orthogonal experiment:starch emulsion concentration is 8%,pullulanase dosage is 20 U/g,enzymatic hydrolysis time is 10 h,the yield of anti-digestible starch is 56.88%,the crystallinity is 25.67%.DCS granules are compact and have smooth surface,clear edge,and layered structure.Rheological results showed that the higher the content of low-digestibility starch,the lower the apparent viscosity of DCS.(2)The effects of different concentrations of KGM on the properties of enzymatic modified corn starch investigated by the analysis of in vitro digestion and physicochemical experiment,including the crystallographic,rheological,and morphological characteristics,and solubility and swelling power.In vitro digestion experiments showed that the anti-digestibility starch content in starch compound(DCSK)reached more than 70%,which was significantly larger than that in DCS sample.X-ray diffraction results showed that the crystallinity of DCSK was 33.88%which was significantly higher than that of DCS(25.67%).Physical experiments show that the addition of KGM increased the apparent viscosity,swelling power and solubility of DCSK.The digestibility and physicochemical properties of DCSK compound are mainly affected on DCSK in two ways:(a)as a physical barrier around the linear chain of linear starch chains;(b)form a network structure and promoted the tight rearrangement of amylose.The observation results of SEM and CLSM shown that,the surface of DCSK sample particles becomes smoother and the number of pores decreases compared to DCS.The starch particles of DCSK were coated by KGM network structure.The higher the content of KGM,the more obvious this coating phenomenon is.This network structure leads to the gathering of starch particles,and promotes the aggregation and regeneration of debranched starch molecules.(3)The effects of DCSK on blood glucose and blood lipid in mice were studied through animal experiments,and the regulation effect of microorganisms was explained by the changes of intestinal microorganisms.Moreover,the regulation effect of metabolites was studied based on metabolomics research methods.The results showed that the DCSK could remit the usual symptoms of diabetic mice(polyphagia,polyphagia and polyuria),and reduce the blood sugar level of the diabetic mice.Biochemical experiments showed that DCSK could reduce the content of total cholesterol,triglyceride,low-density lipoprotein and creatinine,and remit the metabolic disorder of blood lipid in diabetic mice.The hematoxylin-eosin(HE)staining results showed that the morphological arrangement of liver and kindey tissue in the DCSK experimental group mice was normal,and the pathological abnormalities were adjusted.(4)Intestinal microbial experiments showed that DCSK could better regulate the intestinal flora of diabetic mice,mainly by increasing the proportion of bacteroidetes/firmicutes and reducing the abundance of actinomycetes.Metabolomic analysis showed that DCSK complex could deduce metabolic disorders in diabetic mice,Differential metabolism is mainly for sugars,amino acids and fatty acids,such as:D-mannose,L-leucine,L-phenylalanine,linolenic acid,linoleic acid.DCSK complex can make the level of amino acid metabolism normal,reduce the absorption of long-chain fatty acids,and decrease the decomposition of carbohydrates in the mice. |
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