不同巴氏杀菌处理对绵羊乳总蛋白及乳清蛋白二级结构的影响

Effects of different pasteurization treatments on the secondary structure of total proteins and whey protein in sheep milk

中文关键词:  绵羊乳  巴氏杀菌  乳蛋白  二级结构

英文关键词:sheep milk  pasteurization  milk protein  secondary structure

中文摘要:

      目的 分析不同巴氏杀菌处理下绵羊乳蛋白的结构变化, 并以牛乳为对照, 比较二者差异性。方法 分别以低温长时巴氏杀菌(65 ℃ 30 min)、高温短时巴氏杀菌(85 ℃ 15 s)和超巴氏杀菌(121 ℃ 5 s)对绵羊乳、牛乳进行杀菌处理, 探究3种巴氏杀菌处理对绵羊乳和牛乳总蛋白及乳清蛋白二级结构的影响。结果 3种巴氏杀菌处理均会影响绵羊乳总蛋白和乳清蛋白二级结构, 改变乳蛋白原空间结构; 相比总蛋白, 乳清蛋白二级结构稳定性受热处理影响更大(P<0.05), 超巴氏杀菌处理对绵羊乳总蛋白与乳清蛋白二级结构影响最大, 乳清蛋白变性程度最大。绵羊乳与牛乳在3种巴氏杀菌处理方式下蛋白二级结构的变化规律略有差异。结论 3种巴氏杀菌处理下低温长时巴氏杀菌绵羊乳蛋白结构及组成变化最小, 且绵羊乳总蛋白与乳清蛋白二级结构的变化规律与牛乳略有不同, 在绵羊乳液态奶加工时应引起足够重视。

英文摘要:

      Objective To analyze the structural changes of sheep milk protein under different pasteurization treatments, and compare the differences between them with cow milk as a control. Methods Sheep milk and cow milk were sterilized at low-temperature long-term pasteurization (65 ℃ 30 min), high-temperature short-time pasteurization (85 ℃ 15 s) and ultra-pasteurization (121 ℃ 5 s). The effects of the 3 kinds of pasteurization treatments on the secondary structure of total proteins and whey protein in sheep milk and cow milk were explored. Results The 3 kinds of pasteurization treatments all affected the secondary structure of sheep milk total proteins and whey protein, and changed the spatial structure of the original milk proteins; compared with the total proteins, the stability of the secondary structure of whey protein was greatly affected by heat treatment (P<0.05). Among them, ultra-pasteurization had the greatest impact on the secondary structure of total protein and whey protein in sheep milk, and the degree of denaturation of sheep milk whey protein was the greatest. There was a slight difference in the change rule of protein secondary structure between sheep milk and cow milk under the 3 kinds of pasteurization treatments. Conclusion The structure and composition of sheep milk protein in low-temperature and long-term pasteurization under the 3 kinds of pasteurization treatments have the smallest changes. In addition, the secondary structure changes of total proteins and whey protein of sheep milk under 3 kinds of pasteurization treatments are slightly different from those of cow milk, and sufficient attention should be paid to the processing of sheep emulsion milk.