Tianjin University of Science and Technology, China.
Food Sci Technol Int. 2013 Apr;19(2):123-31. doi: 10.1177/1082013212442186. Epub 2013 Jan 16.
The aim of the present study was to investigate the chemical and structural changes in preserved white egg during pickled by vacuum technology. In order to evaluate the changes of preserved egg white during its salted period, sulfhydryl group, disulfide bond contents, and surface hydrophobicity were measured. Fourier transformation infrared spectroscopy and circular dichroism analysis were performed by considering changes of the secondary structural elements, the protein components of egg white was also studied in more detail by electrophoresis. Results showed that the sulfhydryl group and surface hydrophobicity were increased with increasing salting time, whereas a decrease in the disulfide bond contents was observed. Regarding the secondary structure analysis, a decrease in α-helices and β-turns were accompanied by increases in β-sheets and random coils, which indicating a decrease in non-random structure while ever increasing of unordered structure. Electrophoresis shows no significant differences in protein patterns among fresh egg white and samples salting for up to 4 days. Disappearance of most protein was at the 5th day. Single band of ovalbumin can be readily observed from the 6th day to the ripening period finished. Our findings reveal that high pH could induce duck egg white protein aggregation when salting eggs in strong alkaline solution for a long time.
本研究旨在探讨真空腌制过程中皮蛋的化学和结构变化。为了评估腌制过程中皮蛋蛋清的变化，测量了巯基、二硫键含量和表面疏水性。通过考虑二级结构元素的变化，进行了傅立叶变换红外光谱和圆二色性分析，还通过电泳更详细地研究了蛋清的蛋白质成分。结果表明，随着腌制时间的增加，巯基和表面疏水性增加，而二硫键含量减少。关于二级结构分析，α-螺旋和β-转角减少，β-折叠和无规卷曲增加，表明无规结构增加，有序结构减少。电泳显示新鲜蛋清和腌制不超过 4 天的样品之间的蛋白质图谱没有明显差异。第 5 天大部分蛋白质消失。从第 6 天到成熟阶段结束，可轻易观察到卵白蛋白的单一条带。研究结果表明，在强碱溶液中长时间腌制鸭蛋时，高 pH 值可能导致鸭蛋白蛋白聚集。
