Title: Continuous Determination of the Total Acidity and Crude Protein in Soy Sauce and Vinegar by Fixed pH Method
Abstract: In order to establish a kind of new continuous analysis method for determination of the total acidity and crude protein in soy sauce and vinegar,formaldehyde is applied to extract acid materials from the sample,and the fixed pH titration method is used to determine the total acidity with KOH as the standard solution.After removing the excessive formaldehyde,concentrated sulfuric acid and hydrogen peroxide solution are added into the sample solution,and then the sample solution is digested by microwave digestion.After neutralizing the excessive sulfuric acid,formaldehyde is used to change NH4 +into H+.Using KOH as the standard solution,crude protein is determined by fixed pH titration method.The results show that the total acidity(H+)of soy sauce is 0.3626mol/L,the relatively standard deviation is 0.14%(n=6),and the crude protein content is 3.2062g/dL,the relatively standard deviation is 0.44%(n=6);the total acidity(H+)of vinegar is 1.0219mol/L,the relativelystandard deviation is 0.14%(n=6),and the crude protein content is 1.2732g/dL,the relatively standard deviation is 1.5%(n=6).This method is simple,quick,less reagents consumption,without catalyst,lower blank value,less environment pollution.Once sampling can determine two indicators continuously,which greatly improved the work efficiency,and it is more favorable for promotion and application.
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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