The Effects of Strains Inoculation Amount on the Degree of Hydrolysis of Fermented Tilapia Scraps Mixed with Soybean Meal

Mixed strains were used to increase the hydrolysis degree of materials during fermenting. Tilapia scraps and soybean meal were mixed by 1:1 and Bacillus subtilis, yeast and lactic acid bacteria were added. The optimal quantity of strains was determined by hydrolysis degree through single factor experiments and orthogonal experiments. After all, The molecular weight distribution of raw material and products was analyzed by high performance size exclusion chromatography (HPSEC). The results showed that the optimum conditions were as follows: the inoculation amount of Bacillus subtilis, the yeast and the lactic acid bacteria was 0.6‰, 0.06‰ and 0.0015‰, respectively. And the hydrolysis degree of materials increased from 10.3% to 27.3%. The hydrolysis degree of materials increased markedly by adding mixed strains.