Department of Food Science, University of Otago, Dunedin, New Zealand; Department of Biochemistry, University of Otago, Dunedin, New Zealand.
Department of Food Science, University of Otago, Dunedin, New Zealand.
Food Res Int. 2018 Jun;108:465-474. doi: 10.1016/j.foodres.2018.03.075. Epub 2018 Mar 31.
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.
研究了卵转铁蛋白比溶菌酶更易受胃蛋白酶水解，而卵白蛋白的抗蛋白酶水解能力最强。然而，胰蛋白酶可将卵白蛋白水解生成稳定的片段。60°C 热处理 OdEW 溶液对蛋白质的水解作用影响不大，形成的卵白蛋白二聚体对胃蛋白酶的水解作用具有相似的抵抗力。80°C 的加热显著提高了蛋白质的水解作用，因为在胃蛋白酶水解的 30 分钟内，卵白蛋白和形成的蛋白质聚集体完全被水解。将 OdEW 溶液调至 pH 4 并用 695 kJ/kg 的 PEF 处理可提高蛋白质的水解作用，类似于 80°C 的热处理，主要是由于卵白蛋白的酶解增强。因此，PEF 处理可以在最小化蛋白质聚集的同时增加蛋白质消化，从而提高卵白中的蛋白质功能。
