Precision Modification Of Dietary Fiber From Wheat Bran For Improving Intestinal Function

In this study,the wheat bran was used as the raw material.By gradually removing the components including phytic acid,fat,starch,protein and other components from the wheat bran,the effects of the components on the functional properties of the wheat bran were explored.Through three ways of microwave modification,extrusion modification and high pressure modification,the modification scheme was optimized for the properties of wheat bran dietary fiber that could improve the intestinal function,including water holding capacity,oil holding capacity,swelling capacity,cholesterol adsorption capacity,sodium cholate adsorption capacity and other indicators.High-fiber biscuits were prepared and their efficacy in alleviating the intestinal function of constipation was studied by animal experiments.The main research results are as follows:(1)Through single factor experiment,the optimum condition of removing protein from wheat bran was determined as follows: enzyme concentration 6000 U/g,enzymolysis time 150 min,enzymolysis temperature 55 ℃.Under these conditions,the protein content of treated wheat bran was 3.24%.The results of functional characteristics showed that the removal of starch significantly improved the water-holding capacity,oil-holding capacity,swelling capacity,cholesterol adsorption capacity and sodium cholate adsorption capacity of wheat bran,followed by protein,and the removal of fat and phytic acid had the least effect on functional characteristics.The total removal of four components has a significant effect on the functional properties of wheat bran.The yield of dietary fiber is 83.47%,and the water holding capacity,oil holding capacity and swelling power are obviously improved.The effect of component removal on the functional properties of wheat bran was as follows: starch > protein > graisse > phytic acid.(2)The effects of microwave modification,extrusion modification and high pressure modification on the structural properties of wheat bran dietary fiber were investigated,and the samples were characterized by Fourier infrared,X-ray diffraction and thermogravimetric analyzer.Fourier transform infrared(FTIR)results showed that the structure of dietary fiber in wheat bran did not change before and after modification.XRD results show that the crystallinity after high pressure modification is 13.51%,and the crystallization strength after microwave modification and extrusion modification is increased to 16.72% and 17.69% respectively.The results of thermogravimetric analysis showed that the stability of wheat bran dietary fiber prepared by three modification methods was effectively improved.By exploring the effects of different modification methods on the functional indexes of dietary fiber from wheat bran,the results showed that the swelling power of dietary fiber after extrusion modification was second only to that of microwave modification,but the water holding capacity,oil holding capacity,cholesterol adsorption capacity and sodium cholate adsorption capacity were the best.In order to establish a modification method of wheat bran for improving intestinal function,extrusion modification was considered as the best modification method.(3)The optimum addition amount of dietary fiber was determined to be 22% by single factor experiment.The high-fiber biscuits prepared with this addition amount had deeper color and lower hardness.The results of starch digestion experiments in vitro showed that the digestibility of high fiber biscuits was 76.87%,which was lower than that of common biscuits.(4)The slow transit constipation mouse model was established with loperamide hydrochloride.Ordinary wheat bran,modified wheat bran,ordinary biscuits and highfiber biscuits were intragastrical administered for 7 consecutive days to measure the small intestinal propulsive rate and observe the defecation.The results showed that the modified wheat bran and high-fiber biscuits had the effects of promoting the small intestinal peristalsis of the constipation mouse,shortening the discharge time of the first black stool and speeding up the defecation,and improving the fecal water content at the same time,indicating that the modified wheat bran and the high-fiber biscuits prepared by the modified wheat bran had the effects of moistening and smoothing stool and improving intestinal function.