Study On The Preparation Of New Condiment Using Soybean Residues And The By-products Of Fish And Shrimp

In view of the low utilization rate of protein in the brewing process of soy sauce in China and the problems of strong fishy smell,long fermentation period and high salinity in traditional fish sauce,raw materials,including soybean residue,low-value fish and their by-products were applied to make new condiment.In this way,proteases exist in the byproduct of shrimp head can be efficiently used.On the basis of mastering the basic characteristics of raw materials,the preparation procedures of soy sauce was optimized,and the quality index of the final product was detected.The ingredients and nutrients of soybean residue from the soy sauce of Xiamen Gulong Food Co.,Ltd.were investigated.The results showed that the soybean residue was rich in nutrients.Based on dry weight,the contents of protein,carbohydrate,fat were 9.05 g/100 g,9.05 g/100 g,and 4.83 g/100 g,respectively.Therefore,this paper intends to use the natural protease from shrimp head to enzymatically hydrolyze the unused protein in soy sauce and soybean residue,and to prepare a new condiment by combining with the decomposition of low-value fish protein such as blue scab,so as to improve the utilization of resources.The optimum enzymatic hydrolysis condition of the serine protease from Penaeus vannamei shrimp head was investigated at different temperatures,pH values and salt concentrations.The results showed that the optimum temperature and pH of shrimp serine proteinase were 37? and 8.0,respectively.The enzyme activity was inhibited by salt concentration,but changed slightly,and still had 10% activity at 25% salt concentration.Hence,condiments can be prepared with soybean residue,low-value fish and their by-products by adding shrimp head under relative high salinity circumstances.SDS-PAGE was used to detect the optimized conditions for enzymatic hydrolysis of soybean residue and by-products of Decapterus maruadsi.The results showed that the optimum enzyme dosage was 1%,the optimum reaction temperature was 37?,the optimum pH was 8.0,and the optimum salt concentration was 20%.Within 48 hours of enzymolysis under optimum conditions,the protein contents of soybean residue and Decapterus maruadsi by-products were significant.Based on the optimized enzymatic hydrolysis conditions and with the amino acid nitrogen value as the evaluation index,the pilot-scale production of the new condiment was carried out.The results showed that the optimum salt concentration of the new condiment is 20%,and the optimum solid-liquid ratio is 2:1.With the extension of enzymatic hydrolysis time,the changes of total soluble nitrogen,amino acid nitrogen,total soluble solids and soluble salt-free solids showed a trend of rising first and then stabilizing.The contents of volatile base nitrogen and total acid increased first,then decreased,and finally stabilized.The pH value gradually decreased,and finally stabilized.In this experiment,20 L fermentation jar was used,sunshine and night dew were used,and natural fermentation was carried out.Taking amino acid nitrogen value as index,a pilot-scale experiment with a period of 60 days was conducted.After fermentation,the enzymatic hydrolysate was filtered and packaged in a high-temperature sterilized pot to obtain a new condiment product.The product was red-brown,clear and transparent in color,fragrant in taste and without fishy smell.The contents of amino acid nitrogen,total nitrogen and soluble salt-free solids were 0.74 g/100 mL,1.36 g/100 mL,and 18.5 g/100 mL,respectively.No aflatoxin was detected.The contents of heavy metal lead,cadmium and arsenic were less than 0.06 mg/kg,0.0081 mg/kg,and 0.091 mg/kg,respectively,fulfilling the requirements of "seafood condiment GB 10133-2014".In this study,combined with fermentation technology and innovative enzyme engineering technology,the proteases in shrimp head are used to digest low-value fish by-products and soybean residue and to convert them into valuable fish sauce.It solves the problem of heavy taste and low protein utilization of traditional fish sauce.If the technique can be industrialized,the protein utilization rate of raw materials in the domestic soy sauce brewing process will be improved.The problem of low utilization rate of by-products in aquatic products processing will be ameliorated,thus improving the economic benefits of enterprises.