Nikolaidis Athanasios, Andreadis Marios, Moschakis Thomas
Department of Food Science and Technology, School of Agriculture, Aristotle University, GR-541 24 Thessaloniki, Greece.
Department of Food Science and Technology, School of Agriculture, Aristotle University, GR-541 24 Thessaloniki, Greece.
Food Chem. 2017 Oct 1;232:425-433. doi: 10.1016/j.foodchem.2017.04.022. Epub 2017 Apr 6.
A newly developed method of analysis of difference-UV spectra was successfully implemented in the study of the effect of heat, pH, ultrasonication and ethanol on the denaturation of whey protein isolate. It was found that whey proteins exhibit their highest stability against heat denaturation at pH 3.75. At very low pH values, i.e. 2.5, they exhibited considerable cold denaturation, while after heating at this pH value, the supplementary heat denaturation rate was lower compared to that at neutral pH. The highest heat denaturation rates were observed at pH values higher than neutral. High power sonication on whey proteins, previously heated at 90°C for 30min, resulted in a rather small reduction of the fraction of the heat denatured protein aggregates. Finally, when ethanol was used as a cosolvent in the concentration range 20-50%, a sharp increase in the degree of denaturation, compared to the native protein solution, was observed.
一种新开发的差示紫外光谱分析方法成功应用于研究热、pH值、超声处理和乙醇对乳清分离蛋白变性的影响。研究发现，乳清蛋白在pH 3.75时对热变性具有最高的稳定性。在非常低的pH值，即2.5时，它们表现出相当程度的冷变性，而在该pH值下加热后，与中性pH值相比，补充热变性速率较低。在高于中性的pH值下观察到最高的热变性速率。对预先在90°C加热30分钟的乳清蛋白进行高功率超声处理，导致热变性蛋白聚集体的比例降低幅度较小。最后，当乙醇作为助溶剂在20%-50%的浓度范围内使用时，与天然蛋白溶液相比，变性程度急剧增加。
