Technology Exploration Of High-value Utilization Of Soy Sauce Residue

In this study,soy sauce residue was used as a raw material,the fat in the soy sauce residue was extracted under supercritical CO₂system,and the extracted oil was used to prepare biodiesel via transesterification,and then the degreased soy sauce residue was used to prepare soluble dietary fiber?SDF?.Finally,the protein in the residue is enriched and used as protein feed.This study provides a useful reference for solving the environmental pollution problem of soy sauce residue and improving the high-value utilization of industrial and agricultural waste.The main findings are as follows:Under the supercritical CO₂system,the extraction of oil from soy sauce residue can effectively achieve the separation of oil,protein,and crude fiber in soy sauce residue,and the oil extraction rate is as high as 80%.GC-MS analysis of the biodiesel prepared from soy sauce residue oil showed that the composition of biodiesel produced from soy sauce residue oil,although a variety of fatty acid methyl ester components were identified,was mainly concentrated in C17:0,C19:0,C19:1 and C19:2,accounting for 97.64%of the total.It shows that the fatty acid methyl ester composition of soy sauce residue oil is simple and highly concentrated.Such quality is conducive to the processing and utilization of the oil from soy sauce residue.Analysis of the physical and chemical properties of biodiesel produced by this process,in addition to oxidation stability,other indicators have reached the standards of China,the EU,and the United States.By comparing the effects of enzyme,ultrasound and enzyme-ultrasound combination on the yield of soluble dietary fiber prepared from soy sauce residue,the method of enzyme-ultrasonic combination preparation of soluble dietary fiber was determined,and the optimal process conditions were determined as:After the pretreatment and degreasing of the dry soy sauce residue,the SDF yield is the highest at 9.11%under the conditions of 1:40 material-liquid ratio,ultrasound time 6 min,enzyme addition amount 5%,and enzyme hydrolysis time 90 min.The physical and chemical properties and structural analysis of SDF prepared by enzyme-ultrasonic combined method were carried out.Infrared results show that SDF has similar FT-IR spectra to commercially available soybean dietary fiber and soluble soybean polysaccharides,and both have infrared characteristic absorption peaks of polysaccharides.Scanning electron microscopy showed that the supercritical CO₂extraction process will not destroy the structure of dietary fiber in soy sauce residue,and the combined enzyme-ultrasonic treatment can promote the action of cellulase,so that the hydrolysis of cellulase is more sufficient,and the molecular weight is relatively reduced.At the same time,there are many small holes on the surface of the SDF.The results of physical and chemical properties showed that the soluble dietary fiber prepared by enzyme-ultrasonic combined treatment has good water holding capacity,oil holding capacity,and swelling capacity,which are 3.61?g/g?,3.66?g/g?,and 7.28?g/g?.And the oil absorption of the prepared soy sauce residue SDF is significantly higher than that of commercially available soybean dietary fiber and soluble soybean polysaccharide.At the same time,SDF prepared from soy sauce residue has a good adsorption effect on nitrite ions and cholesterol.Determination of protein and crude fiber content in the residue after preparation of SDF,respectively protein 28.03%,crude fiber 10.49%,meet the national standards of protein feed?protein content?20%,crude fiber content?18%?,indicating that after degreasing,preparation of SDF,the soy sauce residue can be used as protein feed.Analysis of the economics of the entire process and found that it has the value of industrial production.