Structure Analysis And Product Development Of Soybean Residue Polysaccharide Fermented By Neurospora And Its Effect On Intestinal Microflora Of Mice With Colitis

The utilization rate of soybean residue is very low in our country.Because of its perishability,pungent taste and roughness,so it is directly discarded,causing great waste.But after the soybean residue are fermented,not only the taste becomes delicate,but also the content of nutrients in the dregs is increased.In this study,the soybean residue were fermented by Neurospora crassa.Firstly,the physicochemical properties of soybean residue before and after fermentation were studied,and the soluble polysaccharides were extracted by water extraction and alcohol precipitation.Secondly,the polysaccharide was isolated and purified by DEAE-52,and the structure of the polysaccharide was analyzed.In addition,by establishing a DSS-induced colitis model in mice,it was studied that polysaccharides from soybean residue fermented by Neurospora crassa alleviate DSS-induced gut barrier damage and microbiota disturbance in mice.Finally,using fermented soybean residue powder and all-purpose wheat flour as raw materials,a dietary fiber biscuit with crisp taste and moderate hardness was developed.The main research contents and results are as follows:1.The soluble polysaccharide was prepared by fermentation with Neurospora crassa,water extraction and alcohol precipitation,and Sevag method for deproteinization.The physicochemical properties and structural characteristics of soluble polysaccharides before and after fermentation were compared.The results showed that the content of total sugar,protein,total flavonoids and total phenols in the soybean residue increased after fermentation.Scanning electron microscope showed that the soluble polysaccharides of the fermented soybean residue were more fluffy and had larger specific surface area.X-ray diffraction showed that the crystal structure of polysaccharides was destroyed by fermentation.The analysis of monosaccharide composition showed that the monosaccharide composition of soybean residue soluble polysaccharide was redistributed before and after fermentation.Fourier transform infrared spectroscopy showed that the fermentation had no significant effect on the structure and functional groups of the soybean residue soluble polysaccharide.Thermogravimetric analysis showed that the food processing temperature should be lower than 200 ℃ to avoid changing the properties of the samples.2.DEAE-52 fiber column chromatography was used to separate and purify polysaccharide from fermented soybean residue.The structure of polysaccharide was analyzed by GC-MS,UV absorption spectrum,nuclear magnetic resonance and Fourier infrared spectroscopy.Three polysaccharide components,namely FSRP-N,FSRP-1 and FSRP-2,were separated by column chromatography.Ultraviolet absorption spectrum analysis showed that the three polysaccharide components did not contain protein,nucleic acid and other impurities.GC-MS showed that the molar ratio of monosaccharides in different components of fermented soybean residue polysaccharide were different.The three polysaccharide components containedβ-pyranose rings.in Fourier transform infrared spectroscopy.NMR analysis of the types of polysaccharide residues showed that the three polysaccharide components contained β-pyranose rings.3.DSS-induced colitis in mice was established for animal experiment of feeding fermented soybean residue polysaccharide.High-throughput sequencing technology was used to detect and analyze the changes of intestinal flora in mice.To study the effects of fermented soybean residue polysaccharide(FSRP)on the composition and diversity of intestinal flora in mice.The results showed that FSRP could reduce the DAI score,increase the colon length,reduce the levels of pro-inflammatory factors IL-1β,IL-6 and TNF-α,and up-regulate the level of anti-inflammatory factor IL-22 in mice.FSRP can significantly improve the expression of E-cadherin and Claudin-1proteins,and improve colon inflammation.Furthermore,FSRP altered the relative abundance of communities and increased the diversity of gut microbiota compared to controls.FSRP can alleviate the symptoms of colitis mice,and its effect may be related to improving the intestinal barrier,reducing the level of inflammatory factors and maintaining the homeostasis of intestinal microflora.4.Developed a functional biscuit with fermented soybean residue and high dietary fiber.The optimum addition amount of fermented soybean residue powder,butter,sugar and egg liquid was obtained by single factor experiment,and the optimum formula was determined by orthogonal experiment.The results showed that the optimal supplemental amount of each component of fermented soybean residue dietary fiber biscuit is: fermented bean dregs powder 10%,butter 50%,sugar 22%,egg liquid 15%,baking soda 1%,salt 0.5%,up and down baking temperature170/180 ℃,bake for 15 min.Biscuits made according to this recipe are crispy in taste and rich in dietary fiber.