不同除菌处理对脱脂驼乳与稀奶油中活性蛋白质的影响

Effects of Different Sterilization Treatments on Bioactive Proteins in Camel Skim Milk and Cream

摘要:

将鲜驼乳离心分为脱脂乳和稀奶油，采用微滤、紫外辐射、巴氏杀菌对脱脂驼乳进行灭菌，采用高温处理对稀奶油进行杀菌，比较非热处理和热处理对微生物去除、活性蛋白质保留及蛋白质和脂肪氧化的影响。与巴氏杀菌相比，微滤、紫外辐射使脱脂乳中细菌总数降低更多，且能完全或部分去除芽孢；1.4 μm微滤和紫外辐射能保留更多的乳铁蛋白和免疫球蛋白G；巴氏杀菌后乳过氧化物酶活力降至杀菌前的1/6，而1.4 μm微滤和紫外辐射样品中乳过氧化物酶活力保留95%以上；多胺氧化酶活力易受紫外辐射影响；1.4 μm微滤使胰岛素完全保留；微滤对天然乳清蛋白的保留率高于巴氏杀菌；与热处理相比，非热处理脱脂乳中蛋白质未发生显著的糖基化反应。与0.8 μm微滤相比，1.4 μm微滤的膜通量更高，且蛋白质的透过率更高，乳清蛋白和酪蛋白透过率分别为95.5%和74.1%。在对稀奶油的高温杀菌中，125 ℃保持5 s能完全杀灭细菌和芽孢，导致蛋白质和脂肪氧化程度较低。将全脂驼乳先分为脱脂乳和稀奶油，各部分灭菌后再混合的处理方法可确保整体有效除菌，同时提高了活性组分的整体保留率。

Abstract:

The fresh camel milk was divided into skim milk and cream. Skim milk was treated by microfiltration, ultraviolet-c radiation and pasteurization, and cream was treated by high temperature treatment. The effects of non-thermal and thermal treatments on removal of microorganism, retention of active protein, and oxidation of protein and lipid were studied. Compared with pasteurization, the results showed that microfiltration and ultraviolet-c irradiation could reduce the total bacterial count and the spores could be completely or partially removed. 1.4 μm microfiltration and ultraviolet-c irradiation retained more lactoferrin and immunoglobulin G. The lactoperoxidase activity decreased to 1/6 after pasteurization. However, the lactoperoxidase activity was more than 95% after 1.4 μm microfiltration or ultraviolet-c irradiation. Polyamine oxidase was susceptible to ultraviolet-c irradiation. Insulin was completely retained after 1.4 μm microfiltration. The retention of native whey protein by microfiltration was higher than that by pasteurization. Compared with thermal treatment, there was no significant glycosylation in non-thermal treated skim milk. Compared with 0.8 μm microfiltration, the membrane flux and permeability of protein was higher than 1.4 μm microfiltration, and the permeability of whey protein and caseins was 95.5% and 74.1%, respectively. In the high temperature sterilization of mixed cream, the bacteria and spores could be killed at 125 ℃ for 5 s, and the degree of oxidation of protein and lipid was low. Firstly, the whole camel milk was divided into skim milk and cream, each part was sterilized and then mixed. This method could ensure the overall sterilizing efficiency and improve the overall retention of active components.