Study On Enzyme-Degrading Reaction Of The Collagen And Enzymatic Processing Technology For Making Gelatin

Taking the place of the conventional liming process the enzyme-degrading reaction of collagen from bovine bones with using AS1.398 neutral protease or pepsin was studied systematically. An optimum condition for making high-quality gelatin was expected to demonstrate in this thesis. Firstly, during the course of decalcifying (demineralizing) pretreatment of degreased bovine bones, the decalcifying rate and the injuring degree of collagen were detected, so that the method of decalcifying from degreased bovine bones and its proper conditions were determined. Secondly, through investigating the stability of AS1.398 neutral protease and pepsin in aqueous solution, the method of how to use these enzymes solutions was established. The measuring data by the self-made gel-strength apparatus and standard Bloom gel-strength apparatus were compared in this thesis, their relationship was found to be linear. The linear regression equation was deduced and tested.Thirdly, further investigations on the collagen enzyme-degrading reaction with AS1.398 neutral protease and pepsin were undergone in details. The influences of the reaction temperature, reaction time, enzyme concentration and the ratio of water to bones on the enzyme-degrading reaction were researched. The factors that influenced the properties of gelatin such as yield, gel strength, viscosity, pH, transparency and chroma, were studied and discussed specially. The fitting reaction condition for making gelatin by enzymic method was established. Under this condition an amplifying experiment upon collagen enzyme-degrading reaction with AS1.398 neutral protease and Pepsin was tried. Fourthly, three terminating methods such as water-washing, pH-adjusting and temperature-regulating for the end of the collagen enzyme-degrading reaction were researched. Temperature regulating method was found more convenient and efficient based on the experimental results. Finally, it was preliminarily to make use of compound enzyme in the collagen enzyme-degrading reaction. It was shown that the obtained gelatin had better chroma and transparency compared with that of using single enzyme. However, further research should be made on the principle of compound enzyme to develop a new promising method for making gelatin.