热处理牛乳中乳蛋白变化的比较蛋白质组学的研究

摘要

试验旨在研究不同热处理方式对牛乳中蛋白组分及含量的影响.生鲜乳经75℃/15 s、125°C/4 s、135℃/4 s和145℃/4 s热处理后,用双向凝胶电泳分离和质谱鉴定的方法分析了生鲜乳以及不同热处理后的乳蛋白的变化.结果发现,与生鲜乳蛋白图谱相比,牛乳经75℃/15 s巴氏杀菌的乳蛋白点的染色密度无明显变化,经135℃/4 s和145℃/4 s热处理后有4个蛋白点的染色密度明显下降,这些蛋白点质谱鉴定为α-乳白蛋白、β-酪蛋白变异体、κ-酪蛋白和免疫球蛋白γ,ELISA方法检测乳中IgG含量的变化验证了双向电泳结合质谱的结果.这些研究结果表明,巴氏杀菌对牛乳中的蛋白组分及含量无明显影响,高温灭菌(135°C/4 s和145°C/4 s)可造成乳中蛋白含量的降低.%To investigate the changes of milk protein after treated with 75 "C/15 s, 125 °C/4 s, 135 °C/4 s and 145 °C/4 s, two-dimensional gel electrophoresis was used to separate proteins samples and mass spectrometry was used to identify differential protein spots. These results showed that four protein spots were down-regulated after treatment with 135 C/4 s and 145 °C / 4 s compared with raw milk and milk treated with 75 C/15 s in which protein profiles had no difference. These protein spots were identified as crlactoalbumin, beta-casein variant, K-casein and Ig y chain. Content of IgG from raw milk and thermal treated milk was detected using ELISA method and in consistent with data of two-dimensional gel electrophoresis coupled with mass spectrometry. These finding indicated that milk protein contents were not affected by treatment with 75 °C/15 s and affected by treatment with 135 °C/4 s and 145 °C/4 s.