Department of Food Science, Engineering, and Technology, University of Tehran, 31587-77871 Karaj, Iran.
Food Funct. 2020 Jul 1;11(7):6632-6642. doi: 10.1039/d0fo00938e. Epub 2020 Jul 13.
The effects of hydrolysis by free and immobilized forms of Neutrase (FN, IN, respectively) and Thermolysin (FT, IT, respectively) and in vitro digestion on the degree of hydrolysis (DH) of egg white proteins, molecular weight distribution of peptides, immune-reactivity and IgE epitopes of egg white proteins were investigated. With FT and IT in the intestinal digests, the proteolysis followed by in vitro digestion produced peptides smaller than 10 kDa. Hydrolysis with the immobilized enzymes had a greater effect than the free enzymes on increasing surface hydrophobicity. The lowest IgE-binding capacity was observed for the intestinal digest of IT-derived hydrolysates (3.3 ± 1.9%). Compared to in vitro digestion, proteolysis showed a significant effect on the immune-reactivity reduction of egg white proteins. Liquid chromatography-tandem mass spectrometry data showed that the most resistant epitopes to enzymatic hydrolysis and in vitro digestion were in ovomucoid, where epitope fragments 1-10, 1-14, 1-20, 4-20, 11-20, 61-74, 71-75 and 101-105 remained intact. Overall, the IgE-binding capacities of egg white proteins were not completely removed after the enzymatic hydrolysis and in vitro digestion due to the presence of intact proteins such as lysozyme and also due to the several immunoreactive peptides derived from egg white proteins.
研究了游离态和固定化形式的 Neutrase（FN、IN 分别）和 Thermolysin（FT、IT 分别）的水解作用以及体外消化对蛋清蛋白水解度（DH）、肽的分子量分布、蛋清蛋白的免疫反应性和 IgE 表位的影响。在肠消化物中使用 FT 和 IT，蛋白水解作用继之以体外消化会产生小于 10 kDa 的肽。与游离酶相比，固定化酶的水解作用对增加表面疏水性的影响更大。IT 衍生水解产物的肠消化物的 IgE 结合能力最低（3.3±1.9%）。与体外消化相比，蛋白水解对蛋清蛋白免疫反应性降低有显著影响。液相色谱-串联质谱数据显示，对酶水解和体外消化最具抗性的表位位于卵转铁蛋白中，其中表位片段 1-10、1-14、1-20、4-20、11-20、61-74、71-75 和 101-105 保持完整。总体而言，由于溶菌酶等完整蛋白质的存在以及蛋清蛋白衍生的多个免疫反应性肽的存在，蛋清蛋白的 IgE 结合能力在酶水解和体外消化后并未完全消除。
