Abstract: Immunoglobulin G (IgG) and lactoperoxidase are bioactive components with high thermal sensitivity in milk. In this study, the changes in the IgG content and lactoperoxidase activity of milk during pasteurization and shelf-life storage were investigated. The results showed that homogenization temperature below 65 °C and homogenization pressure between 15 and 25 MPa had little effect on the two bioactive substances in milk. The combination of 72–76 ℃ and 15 s better retained the bioactive substances and membrane filtration was more effective than regular pasteurization in reducing the microbial load of milk. The IgG content and lactoperoxidase activity in pasteurized milk did not decrease significantly with storage time; however, long-term exposure to light could cause partial inactivation of lactoperoxidase in products with transparent packaging.

Key words: pasteurized milk, bioactive substances, immunoglobulin G, lactoperoxidase, membrane filtration

摘要： 免疫球蛋白G和乳过氧化物酶是牛乳中2 种生物活性物质，研究在巴氏杀菌牛乳加工过程中及货架期内的免疫球蛋白G含量和乳过氧化物酶活性变化。结果表明：采用65 ℃以下的均质温度及15～25 MPa的均质压力处理牛乳对2 种生物活性物质影响较小；72～76 ℃、15 s处理可更好地保留2 种生物活性物质；采用膜滤除菌方式比一般巴氏杀菌效果更佳。巴氏杀菌牛乳中的免疫球蛋白G含量和乳过氧化物酶活性不会随着保存时间的延长而显著降低，但采用透明包装的产品长期暴露在光照下会造成乳过氧化物酶部分失活。

关键词: 巴氏杀菌乳, 生物活性物质, 免疫球蛋白G, 乳过氧化物酶, 膜滤除菌