Abstract:

Casein antibacterial peptide was a novel antibacterial agent, which has characteristics of molecular weight, thermal stability, good solubility in water, no immunogenicity, non-toxic side effects on people and other, so it could be widely used in food, medicine, cosmetics, feed industry. We hydrolyzed casein using alkaline protease and based on alkaline protease concentration, hydrolysis time, hydrolysis temperature viewed as influence factors. We used single factor experiments and centure-composite design center combination method of three factors and three levels experimental design to further opitimaze hydrolysis condition. The results showed that the effect of enzyme concentration, hydrolysis time, hydrolysis temperature were significant. The conditions of casein antibacterial peptide preparation were optimized as following: enzyme concentration 0.67%, hydrolysis temperature 55.73℃, and time 66.07 min. Regression equations predicting casein hydrolysate antibacterial ring diameter could reached 21.66 mm, the average degree of antibacterial ring diameter of three experiments could reached 21.67 mm, which was close to the theoretical maximum, showing that the model could predict the optimal conditions of casein antibacterial peptide preparation.