耐热β-半乳糖苷酶水解乳糖的数学模型研究

In order to provide theoretical guidance for the application of thermostable β-galactosidase in pasteurized low-lactose milk ,a mathematical model of lactose hydrolyzed by thermostable β-galactosidase was established to describe the functional relationship among temperature、enzyme concentration and the hydrolysis rate of lactose in the pasteurization process. The enzyme activity in different temperatures, hydrolysis rate of lactose in milk under different sterilization conditions and enzyme concentration were measured , then the models were fitted by Matlab software based on enzyme activity - temperature and the measured values respectively, and the mathematical model of lactose hydrolyzed by thermostable β-galactosidase was eventually set up based on surface model correction according to the actual production .The results showed that in the temperature range of 63 ~ 66℃, the hydrolysis rate of lactose could reach above 50% by adding appropriate concentration of enzyme. The functional relationship of sterilization temperature、enzyme concentration and the hydrolysis rate of lactose was as following: Y=10^((63-T)/7) (-5.6464×10^(-3) T^3+6.3107×10^(-1) T^2-3.5667T-8.0522×10^2 )E-1.4499×10^3+4.7200×10^1 T-3.4590×10^2 E-4.000×10^(-1) T^2-8.900E^2+5.300TE. The relative error of lactose hydrolysis rate between model prediction and experimental testing was within 3%. Thus, the model is accurate and able to predict the variation tendency of lactose hydrolysis rate during pasteurization process.The model prediction results showed that thermostable β-galactosidase had a good application prospect in the production of pasteurized low-lactose milk.