为改善蛋清的乳化性能,该文以预处理蛋清为原料进行不同pH值偏移辅助糖基化处理,对改性前后蛋清蛋白乳化性的影响,分析了pH偏移辅助后的蛋清蛋白的接枝度、褐变指数、分子质量、粒径和ζ-电位、表面疏水性和游离巯基含量的变化。结果表明,pH偏移处理诱导了蛋白分子的亚基分离和去折叠,使糖基化程度增大、蛋白质分子间静电斥力增强,粒径减小,暴露出更多的疏水基团和巯基,从而提高了糖缀合物的乳化性能。其中,pH 11偏移处理条件下,粒径最小、ζ-电位值最大(-32.2 mV),表面疏水性最好,形成的乳液更稳定,乳化活性指数和乳化稳定性指数分别为14.426 m2/g、38.603 min,乳化稳定性比空白组(12.925 min)和对照组(23.538 min)分别提升了66.52%、39.03%。综上所述,pH偏移辅助糖基化处理能改变蛋清蛋白的结构性质,有效改善其乳化性能。
Aiming to improve the emulsifying performance of egg white, this paper studied the effects of different pH shift-assisted glycosylation treatments on the emulsification of egg white protein before and after modification.The changes of grafting, browning index, molecular weight, particle size ζ-potential, surface hydrophobicity, and free sulfhydryl content of egg white protein after pH shift were analyzed.Results showed that pH shift treatment induced the subunit separation and unfolding of protein molecules, which increased the degree of glycosylation, enhanced the electrostatic repulsion between protein molecules, decreased particle size, and exposed more hydrophobic groups and sulfhydryl groups, thereby improving the emulsifying performance of glycoconjugates.Among them, under the condition of pH 11 shift, the particle size was the smallest, the ζ-potential value was the largest (-32.2 mV), the surface hydrophobicity was the best, and the emulsion was more stable.With the emulsifying activity index (EAI) and emulsification stability index (ESI) being 14.426 m2/g and 38.603 min, the emulsion stability was respectively improved by 66.52% and 39.03% over the blank group (12.925 min) and control group (23.538 min).In conclusion, pH shift-assisted glycosylation treatment could change the structural properties of egg white protein and effectively improve its emulsifying properties.
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