Study On Preparation And Application Of Gelatin From Fish Scale

In the paper,fish scales gelatin was extracted from fish scales of grass carp,which was decalcification by hydrochloric acid. After the properties of fish scales gelatin were studied,the properties of fish scales gelatin and modified KGM composite films were analyzed. The research results are as follows:Through dualquadratic rotary regression orthogonal design experiment with three factors,the effects of the ratio of liquid to material,hydrochloric acid concentration and extraction time on the decalcification rate were investigated,and a mathematical model describing the relationship between the decalcification rate and parameters was developed.The optimal extraction conditions were as follows:the ratio of liquid to material 57.67,hydrochloric acid concentration 3.81% and extraction time 32.33h,and the decalcification rate is 87.62%.The effect of preparation conditions on fish scales gelatin extraction yield has been studied.Optimal conditions for gelatin preparation were as follows:enzymatic dosage 1.2%,the ratio of liquid to material 11.7,enzymolysis time 6h,and predicted value of multiple response optimal conditions was 76.28%.Under the optimal conditions,gelatin was analyzed as the proximate composition of 86.08% protein,12.8% moisture,0.34% lipid and 0.23% ash.The composition,structure and properties of fish scales gelatin were studied.In fish scales gelatin,there were large amount of glycine,proline and alanine,but none tryptophan and cysteine.SDS-PAGE electrophoresis showed that the molecular masses of the fish scales gelatin subunits were about 200 kDa forβ,125 kDa forα1 and 110 kDa forα2,respectively.The gel strength,gelling and melting points of fish scales gelatin which were studied were 254g,17.1℃and 26.8℃respectively.Viscosity of gelatin solution increased with higher concentration of fish scale gelatin,decreased with higher temperature,and increased with higher concentration of NaCl.The concentration of Cd,Pb,As,and Cr was analyzed by ICP-MS.The results showed that Cd was 0.08 mg/kg,Pb,As,and Cr were found in the gelatin.Research has been carried out on oxidation modification to konjac glucomannan and the properties of fish scales gelatin and modified KGM composite films.Through single factor and orthogonal experiments,the effects of reaction conditions on degree of substitution(DS) and viscosity(η) were investigated,and the optimum reaction conditions were obtained as follow:temperature 55℃,pH 11 and reaction time 3 hours.The results showed that the value ofηand DS were 10.13 Pa·s and 0.4926 respectively.Fish scales gelatin and modified KGM composite films characterizes with good compatibility by optic properties analyse.With increasing fish scales gelatin ratio in composite films,tensile strength and water vapor barrier properties of the films increased,but elongation to break and water vapor permeability decreased.