Preparation Of Low-molecular-weight Peptides From Fish Protein By Biological Hydrolysis

Low-molecular-weight peptides were the production from protein incompletely hydrolyzing. Compared with large-molecular-weight proteins, low-molecular-weight peptides were absorbed faster, and also precaution and cure hyperpiesis, anti-oxidation, anti-fatigue, anti-thrombosis, enhancing immunity and so on. This paper studied on hydrolyzing fish protein by enzyme and microbes. The yield of low-molecular-weight peptides was calculated by the methods of biuret and Kjeldahl, which was to determine the optimum conditions of enzymatic hydrolysis and fermentation.Study on enzymatic hydrolysis of fish protein carried out with different proteases, such as Alacalase、 Protamex、 Neutrase and Flavourzyme, which was to individually determine the optimum conditions of enzymatic hydrolysis, and to find which enzyme was the best one. The experimental results showed that Alacalase had the best effect and the optimum conditions were:pH 8.5, reaction time 3 h, enzyme concentration 2.4 AU/kg, temperature 60℃, solid-liquid ratio 1:9.Under these conditions,16.0 g low-molecular-weight peptides could be gained by hydrolyzing fish 100 g, and the purity was 60.1%. The production was easily soluble in water, more bitter and fishier.In this paper, Bacillus natto as zymogen, fish as raw materials, low-molecular-weight peptides were prepared from fish protein hydrolyzed by Bacillus natto, The experimental results showed that optimum conditions of Bacillus natto fermenting fish were:pH 7.5, fish concentration 250 g/L, refilling sucrose concentration 20 g/L, inoculation quantity 3%, fermentation temperature 37℃, fermentation time 24 h.Under these conditions,15.4 g low-molecular-weight peptides could be gained by fermenting fish 100 g, and the purity was 48.4%. The production was easily soluble in water, more delicious and slightly bitter.