Studies On Improving Quality Of Zhacai By Applying Method Of Enzymatic Hydrolysis And Artificially Controlled Fermentation

On the basis of current theory this experiment attempt to apply protease and microbe in the process of zhacai. The purpose is to improve zhacai quality, simplify technological process, shorten action cycle and explore the way to modernization of zhacai process.The first step of this experiment is to select suitable protease and define the condition of enzyme hydrolyzing. Several kinds of lactic acid bacteria most in use for vegetable fermentation are screened and the best cultivation conditions are determined in followed step. Fixing-color and protecting-brittleness are studied, too. At last, the finished product of experiment and several traditional products on sale are compared. The results indicated:1. Protease hydrolysis made contributions to increasing free amino acid (FAN) of product, and the best enzyme is neutral protease combined with papain. The critical volume of neutral protease is 1%, and when beyond 1%, the volume of neutral protease affects FAN value of product very little. Papain showed greater effect than neutral protease on enzyme hydrolysis. The optimal volume of papain is 2%. So, the ratio of neutral protease and papain is 1:2 and the total enzyme volume is 3% can make perfect effect of hydrolysis.2. Water content, salt content of zhacai and temperature, time of hydrolysis can affect enzyme hydrolyzing, so controlling these conditions is important. The results showed followed: dehydrating the sample to 80%⁸5% water content, then using 1% neutral protease combined with 2% papain to hydrolyzing sample for 4h at 45℃ without salt.3. Fixing-color to zhacai should mainly consider the change of chlorophyll, so Zn(Ac)₂ and Cu(Ac)₂ are used as color-fixation on basis of the theory of ion exchange. The volume and ratio of color-fixation and the conditions of fixing-color are determined through experiment: 50mg/kg ZnAc₂ combined 25mg/kg CuAc₂ thermal treat the sample at 70℃ for about 10min. The crisp-keeping effects of CaCl₂ alone and Na alginic acid combined with CaCl₂ are compared, result showed: 0.1% Na alginic acid and then 0.4% CaCl₂ is the best way to crisp-keeping. As for the time, 30min is...