Identification Of Sugars In Soy Sauce And Efficient Utilization Of Wheat Bran

In order to improve the quality and fermentation efficiency of soy sauce,this paper explored the important sugar compounds in different soy sauce and the efficient utilization of wheat bran by different pretreatment,the specific contents were as follows:(1)A total of 214 taste compounds were identified in soy sauce by silane derivatization coupled with gas chromatography-mass spectrometry(GC-MS),including 74 kinds of sugars.The proportion of sugars is highest from 37.24%～77.24%among all taste compounds.In particular,rare sugars such as D-tagatose,aldehydo-L-rhamnose,D-allose,α-D-lyxose,Larabinitol,D-psicose,butane-1,2,3,4-tetrol,α-L-sorbopyranose,L-arabinopyranose,LRibose,D-iditol and D-altrose were detected as the special compounds in soy sauce which come from the sugar metabolism.PCA investigation showed that samples were distinguished by sugars as the first principal component and the general evaluation index(GEI)of samples was consistent with the result of sensory evaluation.Meanwhile,sweetness had the maximum range(from-9.89 to 14.10)in all taste indexes by electronic tongue analysis.(2)Wheat bran,as the raw material of provided the sugar compounds in fermented soy sauce,could become a highly economical sugar source by increasing the conversion rate from cellulose to monosaccharide through treatment.By comparing the pretreatment of 0.1,0.5,1.0,1.5 MPa steam explosion,found that the structure of wheat bran was collapsed from integrity to stratified structure as the SE pressure increased.Fourier transform infrared spectroscopy(FTIR)indicated that cellulose,hemicellulose and lignin were destroyed by 1.0MPa SE pretreatment,the content of which can be decreased about 0.22,0.46 and 0.45 times,respectively.And the reducing sugar and amino acid nitrogen were greatly increased.(3)Maillard reaction is accompanied by the process of soy sauce fermentation,which is the basis of rapid production of flavor components.The Maillard reaction of glutamic acid and wheat bran treated with 1.0MPa were carried out at pH=6.6 and 100℃ for 0-48h.The end point of Maillard reaction was determined to be 30h by detecting the physicochemical indexes of Maillard reaction products.Furthermore,sensory evaluations in SE treated Maillard reaction products(MRPs)were much stronger than the control,and 11 key aromaactive substances such as nonanal,decanal,dodecanal,benzeneacetalehyde,octanal,trans,trans-2,4-nonadienal,1-hexanol,linalool,y-nonalacone,2-methoxy-4-vinylphenol and guaiacol were identified in the SE treated of 1.0MPa.Especially,the contents of aroma compounds(pyrazines,nitrogen oxides)increased dramatically in the MRPs of SE treatment.This indicates that SE and MR are efficient techniques for improving the flavor onto wheat bran,as SE-1.0 exhibited polysaccharide conversion capacities batter than other pretreatment.