包被工艺条件对植酸酶热稳定性的影响

考察了不同种类的糖、盐及浓度在干热及湿热的情况下对残存酶活的影响，通过正交实验，确定包被工艺优化条件为：以多孔淀粉为载体，采用流化干燥法取得；包被中蔗糖的添加量为40mg／g酶，氯化钠包覆用量为淀粉质量的10％，明胶作外包被，用量为淀粉质量的1.5％，得到包埋颗粒，其包埋率为82．8％，包埋后，水分活度大于0．35时，包被酶在干热的情况下残存酶活比原酶有较大的提高，残存酶活提高8．7％，湿热的情况下，残存酶活提高58．3％，胃蛋白酶对其的损坏作用也明显减小.

Increased thermostability of phytase by coated conditions

The Effects of the various sugars, salts and their c oncentration on the relative retaining activites of phytase under the dry heat c ondition and the wet heat condition were investigated. Through results indicated that trehalose was more effective than sucrose, bur for economy, sucrose was sti ll selected. The optimeal composition of coat was obtained through orthogonal te sts as follows:with porous starch as the carrier, the satisfactory adding amount was 40 mg/phytaseg, the content of NaCl was 10% w/w to starch, gelatin was 15% w/w to starchThe coated rate is 828?ter coating, when water ac tivity is higher than 035The relative retaining activites of coated phytase is much more than the original under the condition of thermostability After th e coating, the relative retaining activites of phytase under the dry heat condit ion in oven was more than that of free phytase in the same situation. Under the condition against steam treatment, the relative retaining activites of phytase was also much better than that of free phytase, and the degrade of coated phyt ase by pepsin was obviously lessened