Protein susceptibility to in vitro gastrointestinal digestion of ovomucin-depleted egg white (OdEW) adjusted to pH 4, 5, 7 and 9 and processed by heat (60 and 80 °C for 10 min) or pulsed electric fields (PEF) (1.4–1.8 kV/cm, 259–695 kJ/kg) was studied by assessing peptide production, proteolytic pattern, and the final peptide profile. Ovotransferrin was more susceptible to pepsin hydrolysis than lysozyme, with ovalbumin showing the highest proteolytic resistance. Ovalbumin was, however, hydrolyzed by pancreatin to produce a stable fragment. Heat treatment of OdEW solutions at 60 °C had little impact on protein susceptibility with the ovalbumin dimers formed having a comparable resistance to pepsinolysis as ovalbumin. Heating at 80 °C significantly enhanced protein susceptibility, as ovalbumin and protein aggregates formed were completely hydrolyzed within 30 min of pepsinolysis. Adjusting OdEW solution to pH 4 and treating with PEF at 695 kJ/kg enhanced protein susceptibility, similar to heat treatment at 80 °C, mainly owing to the enhanced enzymatic hydrolysis of ovalbumin. PEF processing can, therefore, increase protein digestion while minimizing protein aggregation, which will enhance protein functionality in egg whites.

蛋白质对体外的敏感性肠溶消化的卵蛋白减少的蛋清（OdEW）的pH值调节为4、5、7和9，并通过加热（60和80°C持续10分钟）或脉冲电场（PEF）（1.4–1.8 kV / cm，通过评估肽的产生，蛋白水解模式和最终的肽谱，研究了259–695 kJ / kg）。卵转铁蛋白比溶菌酶对胃蛋白酶水解更敏感，卵清蛋白显示出最高的蛋白水解抗性。然而，卵清蛋白被胰酶水解以产生稳定的片段。OdEW溶液在60°C的热处理对蛋白质的敏感性几乎没有影响，所形成的卵清蛋白二聚体具有与卵清蛋白相当的对胃蛋白酶解的抗性。加热到80°C会显着增强蛋白质敏感性，因为在胃蛋白酶溶解后30分钟内卵白蛋白和形成的蛋白质聚集体会完全水解。将OdEW溶液调节至pH 4并以695 kJ / kg的PEF处理可提高蛋白质敏感性，类似于在80°C的热处理，这主要是由于卵清蛋白的酶促水解作用增强。因此，PEF加工可以增加蛋白质消化率，同时最大程度地减少蛋白质聚集，这将增强蛋白的蛋白质功能。