Research On The Rapid Preparation Of Fish Sauce From Silver Carp By The Three-Step Method

In this research,the squid processing waste is used as raw material,and the flavored fish sauce is quickly prepared by three-step method.Through the organic integration of enzyme engineering technology,modern fermentation technology and flavor optimization technology,it provides an effective preparation for flavor freshwater fish sauce.This research provides a new way for high value utilization of carp.The major results of this research are summarized as follows:(1)The first step of fish sauce was prepared by a two-enzyme step-by-step enzymatic hydrolysis technique.The preparation technology of squid sauce was optimized by single factor test and orthogonal test.The optimal preparation conditions were obtained: fixed pH 7.0,first added 2.5% neutral protease,and hydrolyzed at45°C for 5 h;then added 2.0% flavor protease and hydrolyzed at 55°C for 3 h.The amino nitrogen content and total nitrogen content of the fish paste prepared under these conditions were 5.93±0.30 mg/mL and 8.12±0.32 mg/mL respectively.(2)The second step of preparation of fish sauce is carried out by using the koji fermentation technique.According to the fermentation single factor experiment and the Box-Benhnken test design,a regression model of fermentation temperature,fermentation time and soybean seed koji addition was established,and the response surface was optimized.According to this model,the optimal process parameters for the fermentation were determined to be fermentation temperature 37°C,fermentation time 11 d,soybean seed koji addition amount 32.45%,and salt addition amount 10%.Under these conditions,the amino acid content of fish sauce was 8.56±0.21 mg/mL and the total nitrogen content was 12.15±0.18 mg/mL.(3)The third step of fish sauce was prepared by Maillard reaction flavor optimization technology.By studying the effects of Maillard reaction temperature,reaction time,initial pH,D-xylose addition and L-alanine addition on the flavor of fish sauce after fermentation,the optimal range of each factor was determined.The orthogonal test was used to optimize the process conditions,and the reaction time was15 min,the temperature was 100 °C,the D-xylose addition amount was 0.4%,the initial pH was 7.0,and the L-alanine addition amount was 0.3%,which was the optimum condition for the Maillard reaction optimization process.The conclusions indicated that the comprehensive sensory score reached 8.64±0.20.(4)The odor information and GC-MS detection of the fish-boil samples collected by the electronic nose were used to compare and analyze the odor difference in the fish sauce prepared by the two kinds of commercially available fish sauce and the three-step method.And determine what is the difference between the ingredients.The electronic nose test showed that there was a significant difference between the fishsauce prepared by Real THAI fish sauce,Pu-Yuan fish sauce and three-step method.The difference in odor was mainly manifested in small molecular nitrogen oxides,short-chain alkanes,inorganic and organic sulfides.The small molecule oxynitride contained in the fish sauce prepared by the three-step method increased significantly,and the organic and inorganic sulfur compounds also increased.According to the GCMS test,the substances of organic acids such as DHA and EPA increased in the fish sauce prepared by the three-step method,and 2-ethyl-3,5-dimethylpyrazine was detected.This may be an amino acid.Generated by a Maillard reaction with D-xylose.The increase of ?-phenylethyl alcohol,ethyl maltol,hydrogenated cinnamic acid,ndodecanoic acid and the like makes the flavor of the low-salt fish sauce which is rapidly prepared by the three-step method more excellent.