The Properties Of Ginger Protease And The Effection On Clarification Ginger Juice

Ginger is a kind of food with high nutritional and officinal value,and ginger protease is a new plant protease that widely used in food and other fields.Ginger protease was extracted by acetone from ginger,and the application of ginger protease in clarifying ginger juice was studied in this paper.1.The extraction of ginger protease:fresh diced ginger was homogenized with 2 part(w/v)cold buffer.The mixture was placed at 4? for 15min before filtrated,adding acetone which 1.6 times of ginger to the filtrate slowly,centrifugal 4000r/min for 10min,crude ginger protease powder was attained after extracting and freeze-drying,of which the enzyme yield was 1.97%,and the specific activity was 90.97U/mgPro.2.The properties of ginger protease were studied,The results showed that the optimum temperature was 60? and the optimal pH was 6.0.Mercaptoethanol,KCl,MnCl2,FeCl2,EDTA-Na2 and isoascorbate had activation effect on ginger protease;CaCl2 and MnCl2 had activation function too,especially at low concentrations;ZnSO4 and CuSO4 inhibited the enzyme activity.3.Ginger protease(endogenic)can hydrolyze 56%protein at 45? for 60min,which played an important role in solving the sedimentation happened in ginger juice.The ginger juice was treated by PAM,PVP.sodium alginate,Pectinex XXL and chitosan.The results indicated that chitosan and Pectinex XXL were better than PAM,PVP and sodium alginate on clarifying the ginger juice.The optimum clarification technology:ginger juice was keeping at 45 ? for 60min,the addition amount of chitosan was 0.08%,going on keeping at 60? for 10min.Then boiled the juice for 5min,filtered,sterilization.The light transmittance of finished ginger juice can reach 95.9%at wave length 650nm.The preliminary study on clarification of ginger juice laid the foundation for further development and utilization.