Study On Technology Of Small Peptide Production By Surimi Wash Water

Recently, surimi production was increasing, and surimi wash water containing large of protein was discarded,which not only wasted resources, but also polluted environment. Therefore, recovered water soluable proein from surimi wash water, on the one hand, increased profits of enterprises; on the other hand, had great significance for constructing resource-saving and environment-friendly society. The research, contents and results as follows:First, recovered water soluable protein using electric point method,chitosan and sodium alginate method.Optimized the condition using single factor experiments and orthogonal test. Results showed:the optimum method was sodium alginate method.When content of protein in SWW was 9.0mg/mL, the optimum condition of sodium alginate was: pH4.0,temperature 25℃,addition of alginate of flocculant 1.5mL.,recovery rate of protein83.97%,light transmittence91.50%,COD reduction 53.55%.Second, recovered fish protein as raw material, the research studied the optimum enzymatic hydrolysis conditions of sutilains, flavourzyme, trypsin, papain, and protamex through sigle factors experiments.. Degree of hydrolysis and recovery rate of nitrogen as index, the effects of 5 kinds of proteases were compared. According the result of comparison, sutilains, flavourzyme and protamex were selected for fish protein hydrolysis.Third, selected sutilains and protamex for sole enzymolysis technology. respectively through the orthogonal experiments, optimized parameters of sutilains and protamex for fish protein hydrolysis. Orthogonal tests showed :the protamex was the better enzyme for fish protein hydrolysis.The optimum condition was :temperature 50℃, pH8.0,L/S6:1, addition of enzyme1.5%, time4.0h. Degree of hydrolysis41.38%,recovery rate of nitrogen 90.45%,sensory evaluation4.2point. Fourth, established the optimum condition of 2 kinds of stage enzymatic hydrolysis technology respectively through orthogonal test. And the results showed: the stage enzymatic hydrolysis of protamex and flavourzyme was the better method. The optimum condition was: L/S6:1, the condition of first stage for protamex was: addition of enzyme1.0%,temperature50℃,pH8.0,time1.5h;the optimum condition of second stage for flavourzyme was: addition of enzyme1.0%,temperature55℃,pH7.0, time3.5h. Degree of hydrolysis46.25%, recovery rate of nitrogen 91.15%, sensory evaluation 4.8 point.Fifth, decolorized the hydrolyzate using active carbon and established the optimum condition through orthogonal test:pH4.0, amount of active carbon 0.5g/100mL hydrolyzate,decolorization time40min,temperature40℃, recovery rate of nitrogen 90.25%,decolorizing rate 69.88%,sensory evaluation 7.5 point.Sisth, Determination of molecular weight of fish protein hydrolysate prepared by the optimum hydrolysis condition by G-50gel chromatography. Result showed: small peptide less than 2000Da was 52.17%.