State Key Laboratory of Food Science and Technology, College of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, P.R. China; School of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang University, Nanchang, 330047, Jiangxi, PR China.
School of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang University, Nanchang, 330047, Jiangxi, PR China; Jiangxi-OAI Joint Research Institute, College of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, P.R. China.
J Dairy Sci. 2022 Nov;105(12):9476-9487. doi: 10.3168/jds.2022-22287. Epub 2022 Oct 26.
Dairy processing can alter the digestion stability and bioavailability of cow milk proteins in the gastrointestinal tract. However, analysis of stable linear epitopes on cow milk allergens that could enter into intestinal mucosal is limited. Thus, this study aimed to investigate the digestion and transportation properties and residual allergen epitopes entering into gastrointestinal mucosa of 3 commercial dairy products, including pasteurized milk (PM), ultra-heat-treated milk (UHTM), and dried skim milk (DSM). In this work, the digestive stability of the 3 kinds of dairy products has been performed in a standard multistep static digestion model in vitro and characterized by Tricine-SDS-polyacrylamide gel electrophoresis and reversed-phase HPLC. With respect to gastrointestinal digestion in vitro, the main allergens including β-lactoglobulin (β-LG), α-lactalbumin (α-LA), and caseins were degraded gradually, and the resistance peptides remained in the PM with a molecular weight of range from 3.4 to 5.0 kDa. Simultaneously, the potential allergenicity of the cow milk proteins was diminished gradually and is basically consistent after 60 min of gastrointestinal digestion. After gastrointestinal digestion, the remaining peptides were transported via an Ussing chamber and identified by liquid chromatography-MS/MS. By alignment, 10 epitopes peptides were identified from 16 stable peptides, including 5 peptides (AA 92-100, 125-135, 125-138, and 149-162) in β-LG, 2 peptides in α-LA (AA 80-93 and 63-79), 2 peptides in α-casein (AA 84-90 and 125-132), and 1 peptide (AA 25-32) in α-casein were identified by dot-blotting mainly exist in UHTM and PM. This study demonstrates dairy processing can affect the digestion and transport characteristics of milk proteins and in turn alter epitope peptides release.
乳制品加工可以改变胃肠道中牛奶蛋白的消化稳定性和生物利用度。然而，对于能够进入肠道黏膜的牛奶过敏原的稳定线性表位的分析还很有限。因此，本研究旨在研究 3 种商业乳制品（巴氏杀菌奶（PM）、超高温处理奶（UHTM）和脱脂奶粉（DSM））的消化和转运特性以及进入胃肠道黏膜的残留过敏原表位。在这项工作中，在体外标准分步静态消化模型中对 3 种乳制品的消化稳定性进行了研究，并通过 Tricine-SDS-聚丙烯酰胺凝胶电泳和反相 HPLC 进行了表征。就体外胃肠道消化而言，主要过敏原包括β-乳球蛋白（β-LG）、α-乳白蛋白（α-LA）和酪蛋白逐渐降解，PM 中残留的分子量在 3.4 到 5.0 kDa 范围内的抗性肽。同时，牛乳蛋白的潜在致敏性逐渐减弱，在 60 分钟的胃肠道消化后基本一致。胃肠道消化后，剩余的肽通过 Ussing 室转运，并通过液相色谱-MS/MS 进行鉴定。通过比对，从 16 个稳定肽中鉴定出 10 个表位肽，包括β-LG 中的 5 个肽（AA92-100、125-135、125-138 和 149-162）、α-LA 中的 2 个肽（AA80-93 和 63-79）、α-酪蛋白中的 2 个肽（AA84-90 和 125-132）和α-酪蛋白中的 1 个肽（AA25-32）主要存在于 UHTM 和 PM 中。本研究表明，乳制品加工会影响乳蛋白的消化和转运特性，并进而改变表位肽的释放。
