Abstract: In order to prepare highly active antibacterial peptides power, casein was extracted from fresh milk and then hydrolyzed with one of four different proteases (neutral protease, alcalase, trypsin and papain). Casein hydrolysates prepared with papain exhited stronger inhibitory effects on Escherichia coli, Salmonella and Staphylococcus aureus than those prepared with neutral protease, alcalase or trypsin. Using one-factor-at-a-time and orthogonal array design methods, the optimal hydrolysis conditions for the preparation of highly active antibacterial casein hydrolysates with papain were determined as following: 50 ℃ of hydrolysis temperature, 4.5 h of hydrolysis time, 4500 U/g of enzyme amount, pH 5.5, and 6 g/100 mL of substrate concentration. Moreover, we found that both the prepared casein hydrolysates and their lyophilized powder had stable antimicrobial activity. Meanwhile, the lyophilized powder showed slightly stronger antimicrobial activity.

Key words: bovine casein；milk-derived materials；optimizing；antimicrobial activity

摘要： 为制备抗菌活性较好的肽粉乳基料,以新鲜牛乳为原料提取酪蛋白,以酪蛋白酶解物对大肠杆菌、沙门氏菌和金黄色葡萄球菌的抑菌圈直径为指标,从木瓜蛋白酶、碱性蛋白酶、中性蛋白酶和胰蛋白酶中筛选出一种蛋白酶水解牛乳酪蛋白,并通过单因素试验和正交试验确定该酶水解牛乳酪蛋白优化水解条件。结果表明：木瓜蛋白酶水解牛乳酪蛋白,其酶解物对3种菌均有较好的抑制作用;优化水解工艺条件为：酶解温度50℃、酶解时间4.5h、加酶量4500U/g、pH5.5、底物质量浓度6g/100mL;牛乳酪蛋白酶解物及初级肽粉乳基料稳定性均较好。

关键词: 牛乳酪蛋白; 乳基料; 优化; 抑菌活性