Study On Quick Fermentation Production Technology Of Low Salt Fish Sauce

Using yellow stripe trevally(Selaroides leptolepis) as raw material, studied on quick fermentation production technology of fish sauce. Trypsin, papain enzymatic hydrolysis conditions and double-enzyme fractional hydrolysis conditions, preparation of koji of Aspergillus oryzae and fermentation technology of fish sauce, fish sauce flavor improve conditions, allocation formula and sterilization methods were studied. After enzymatic hydrolysis and fermentation, volatile constituents and 16 kinds of amino acids of the sample were determined. While the physical and chemical index, the microbial indicators and the sensory evaluation of fish sauce were determined.The results show that the optimum conditions of single enzyme solution for trypsin at the following conditions: solid to liquid 1:5(g/g), the enzyme concentration 2.0%(g/g), pH 8.0, hydrolyzed for 4h at 45℃, and the degree of hydrolysis was 30.51%. For papain: solid-liquid ratio 1:4(g/g), the enzyme concentration 2.0%(g/g), pH 6.0, hydrolyzed for 4h at 60℃, and the degree of hydrolysis was 18.51%. The optimum conditions of double-enzyme fractional hydrolysis as follows: first, added trypsin, the solid-liquid ratio 1:5(g/g), the enzyme concentration 2.0%(g/g), pH 8.0, hydrolyzed for 5h at 45℃, then add papain, enzyme concentration 1.6%(g/g), pH 6.3, hydrolyzed for 3.5h at 61℃, in this conditios, the degree of hydrolysis was up to 43.23%. The optimal parameters for preparing Koji as follows: bran and surimi proportion 1:2(g/g), amount of inoculation 0.6%(g/g), amount of water for medium 200%(mL/g), cultured at 34℃ for 5d, the enzyme activity reached 2 376.86 U/mL. The optimum fermentation process parameters of fish sauce as follows: bran and enzymatic hydrolysate 1:8(g/g), koji 0.6%(g/g), salt 9.7%(g/g), fermented at 32℃ for 11 d, and the content of amino nitrogen were 1.327g/100 mL. The optimum conditions of improve fish sauce flaver as follows: first add yeast powder 1.5%(g/g), after reaction 90 min at 25℃, add β-Cyclodextrin 1.0%(g/g), response 60 min at 40℃. Added white granulated sugar 9%(g/g) to fish sauce, could bing a better taste and flavor. Sterilization condition was at 100℃ for 15 min. The volatile flavor components of fish enzyme solution were total of 29 species, including 11 kinds of esters, 4 kinds of acids, 3 kinds of alcohols, 3 kinds of aldehydes, 3 kinds of hydrocarbons, 1 kind of nitrogen and sulfur compounds, 3 kinds of other heterocyclic compounds. The volatile flavor components of fermented solution were total of 30 species, including 9 kinds of alcohols, 8 kinds of esters and ketones, 3 kinds of acids, 2 kinds of hydrocarbons, and 3 kinds of nitrogenous compounds, 2 kinds of sulfur compounds, and 3 kinds of other heterocyclic compounds. Comprehensive analysis of the measurement results, the volatile compounds of fermented solution can be given more flavor ingredients for fish sauce, fermentation can well improve the flavor of hydrolysates. Total content of the 16 amino acids of fish sauce was 2.5g/100 g, the highest content of glutamic acid was 0.513g/100 g, followed by aspartic acid was 0.254g/100 g. Total nitrogen content of fish sauce reached 2.056g/100 mL, the content of amino nitrogen was 1.286g/100 mL, the content of salt was 9.62%(g/g), total acid of colonies and coliforms were less than the national standards, pathogenic bacteria, were not chected out. By using double-enzyme fractional hydrolysis and temperature control fermentation by using koji of Aspergillus oryzae, the fermentation time shortened from 1~3 years to 2~3 weeks, compared with the naturally fermentation, the content of salt reduced from 27%~29% to 10%, compared with the traditional fermentaion.