Study Of Material Basis And Quantitative Evaluation Of Flavor Substances In Soy Sauce Surface Residue

With the improvement of living standard,the table food is more and more rich,and the consumption of soy sauce is also increasing.The annual output of soy sauce in China is about 7 million tons.Soy sauce residue(SSR)is the largest by-product of soy sauce.Improper treatment will not only lead to waste of resources,but also cause environmental pollution.The efficient and comprehensive utilization of SSR has become a technical problem which need to be solved.In this paper,the soy sauce surface residue(SSSR)with strong flavor was selected as the raw material.Firstly,the electronic tongue was used to optimize the flavor of SSSR extract to get an extract with better flavor;secondly,the quantitative method was used to clarify the non-volatile and volatile flavor substances composition of the SSSR extract.Based on that,rough separation was used to explore the flavor contributors of SSSR extract and got a better seasoning,which provided a new idea for preparing high-quality seasoning and expanding the application field of SSR.On the basis of chemical composition of SSSR,the differences of non-volatile flavor substances,volatile flavor substances and taste between SSSR and soy sauce were analyzed to clarify the characteristic chemical composition and taste of SSSR.The results showed that the total amount of biogenic amines in the SSSR were at a safe level,the content of soluble substances were as high as 73.53%,the composition of protein,sodium chloride and carbohydrate in the SSSR were similar to that of soy sauce,and the content of umami amino acids and hydrophobic amino acids were rich.Under the same concentration,the content of volatile substances in the SSSR extract was significantly higher than that of soy sauce.Among them,4-Ethylguaiacol,2-heptanone,phenylethanol,4-ethylphenol and 1-octene-3-ol were the characteristic volatile flavor substances in the SSSR extract.Through single factor and orthogonal experiments,it was found that the p H had the most significant effect on the overall taste of the SSSR extract.The optimal extraction condition of the SSSR extract was determined as follows: extracted for 90 minutes at 75? in p H 5.50.By adjusting the p H value,the SSSR extracts with significant taste difference were obtained.Combining the correlation analysis and partial least square analysis,the characteristic composition of non-volatile flavor substances in the extract were studied.It was found that the molecular weight distribution and amino acid composition of the SSSR extracts were highly related to its taste quality;the key volatile flavor substances of different p H extracts were similar,mainly included 3-Methylbutyraldehyde,2-methylbutyraldehyde,phenylacetaldehyde,benzaldehyde,4-Ethylguaiacol,acetone,2-methylpropionaldehyde,3-methylthiopropionaldehyde,4-ethylphenol,3-methylbutanol,n-hexanal,furfural,dimethyl disulfide,1-octene-3-alcohol and 2-Methylbutyric acid.Among them,dimethyl disulfide would increase with the p H,and the high content of it would lead to the bad smell.Combined with the result of correlation analysis and partial least square analysis,ultrafiltration was chose to separate and enrich the non-volatile flavor substances in the SSSR extract.The results showed that the fraction of < 1000 Da with a high umami and salty taste but lowest bitterness.In addition,freeze-drying would lead to the loss of 42.01% of volatile flavor substances,especially 81.81% of dimethyl disulfide(bad smell),suggesting that freeze-drying could be an effective way to remove the bad smell of SSSR extract.