Optimization of Enzymatic Hydrolysis-Fermentation Process for Preparing Fish Juice

In this paper, using Pneumatophorus japonicus as raw material, using single factor and orthogonal experiments, the process of preparing fish juice by enzymatic hydrolysis-fermentation method was optimized, and physical and chemical indicators and microbial testing were carried out, as well as amino acid and biogenic amine determination, so as to analyze the nutrition and safety of the product. The results showed that: The raw material used neutral protease/flavor protease(1:2, w/w), enzyme addition amount 800 U/g(w/w), solid-liquid ratio 1:4(w/v), enzymatic hydrolysis at 50 ℃ for 6 h, after that, the degree of hydrolysis was 69.67%±0.47%. And on this basis, it was fermentation at 40 ℃ for 21 d with soybean meal koji(14%, w/w) and salt(9%, w/w). The fermentation broth obtained under this condition was reddish-brown, had the inherent aroma and taste of fish-flavored condiments, and the content of amino acid nitrogen reached 0.81±0.02 g/100 mL. In the fermentation broth, the delicious amino acids Asp and Glu accounted for 27.20%; the essential amino acids accounted for 44.95%; the histamine content was only 13.35 mg/L. The fermentation broth could be used as a base material for the preparation of fish sauce or other seafood condiments. The experiment provides a new way for the processing and utilization of Pneumatophorus japonicus, and has good development prospects and market expectations.