Extraction And Purification Of Ginger Protease And Application In Soybean Cheese Production

Ginger protease is a kind of new protease resources which is similar with papain. Like papain, ginger protease also has curd characteristic. However, there is no depth research about it. Because of the limitation of papain, it is necessary to research new resources. In this experiment, ginger is taken as experimental material. I studied extraction and purification methods of ginger protease and applied them into production of soybean cheese. In addition, I optimized the processes of producing ginger protease and soybean cheese and confirmed the optimized process of producing soybean cheese, using ginger protease as rennet. The contents are as following:1. Extraction and purification methods of the ginger proteaseGinger was used as the experimental material, with0～20%、20～40%、40～60%、60～80%、80～100%ammonium sulfate saturation, soymilk coagulation activity as an index, the optimum conditions of ammonium sulfate saturation was20～60%. When ammonium sulfate saturation was20～40%、40～60%,soymilk coagulation activity was29U/mg、33U/mg.Glucan gelG-75chromatographic column connected with protein purification device, according to280nm absorbance value graph, the optimum conditions of purify ginger protease were derived. They are, the gel chromatography column bed height was50cm, sample quantity was3mL, elution rate was1.5mL/min. The optimal technology of extracting ginger soymilk coagulated activity was129.53U/mg; purified ratio was2.46times of ginger.2. Optimized soy-milk solidification conditionsIn the process of optimized soy-milk solidification conditions, solidification temperature、 holding time、added ginger protease amount、the ratio of soybean and water as factors, hardness, spring and viscosity as an indexes, the optimum conditions of solidification soymilk were derived. The solidification soymilk temperature was60℃, holding time was2h, the adding amount of ginger protease0.4%, the ratio of soybean and water was1:9.Through the response surface experiment, solidification temperature, holding time, amount of ginger protease as factors, it was concluded that the best process is that solidification temperature is60℃、holding time is2h、added ginger protease amount is0.4%.3.Ginger protease will be applied in soybean cheese, optimized the process of soybean cheese conditions, sensory evaluation as index, the optimum conditions of removal soybean smell is to do microwave treatment for10min.In the optimized the process of fermentation soy-milk,the best conditions were that ratio of thermophilic streptococcus and lactobacillus Bulgaria is1:1, lactic acid bacteria addition is4%fermented at37℃for50min; the addition of Cacl2is2mM. The content of protein, fat, and moisture of soybean cheese are16.8%,11.6%and46.2%. Through the sensory evaluation, soybean cheese is in accordance with GB standards.