Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North 4474, New Zealand.
School of Food and Advanced Technology, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand.
Food Funct. 2022 May 23;13(10):5654-5666. doi: 10.1039/d1fo03740d.
This study aimed to determine the ability of actinidin, a cysteine protease in green kiwifruit (), to hydrolyse wheat proteins and gluten-derived immunogenic peptides from a commonly consumed food matrix (bread) using a combined an oro-gastrointestinal tract (GIT) model. A chewed and spat composite bolus of bread was digested with or without purified actinidin using a human gastric simulator (HGS). Gastric digestion was conducted for 150 min with gastric emptying occurring at different time points. Emptied samples were immediately digested under simulated small intestinal conditions. Gastric and small intestinal aliquots were collected to quantify peptide profiles and nine marker immunogenic peptides (by untargeted and targeted mass spectrometry, respectively), R5 epitopes (by monoclonal antibody-based competition assay), and free amino groups released by digestion (by the -phthaldialdehyde method). There was a significant effect ( < 0.05) of actinidin and digestion time on the hydrolysis of wheat proteins and the amount of gluten R5 epitopes of that material emptying the HGS. Actinidin accelerated 1.2-fold the gastric hydrolysis of wheat proteins during the first 20 min of digestion, which was reflected in a faster (5.5 μg min) reduction in the evolution of R5 epitopes. Actinidin accelerated ( < 0.05) the rate of disappearance of most of the immunogenic marker peptides. For example, in the first 20 min of small intestinal digestion, the 33-mer peptide decreased ( < 0.05) 2-fold faster (0.25 . 0.12 μg g of bread per min) in the presence of actinidin than in the control. Untargeted peptidomics showed actinidin decreased the amounts of known immunogenic peptides in the simulated small intestinal digestion. These findings demonstrated that actinidin accelerates the hydrolysis of wheat proteins and known gluten immunogenic peptides in a commonly consumed food matrix (bread) in a combined an oro-GIT digestion model.
本研究旨在利用口腔-胃肠道（GIT）联合模型，确定存在于绿奇异果（）中的半胱氨酸蛋白酶——菠萝蛋白酶对小麦蛋白和来源于面筋的免疫原性肽的水解能力，该模型使用咀嚼并吐出的复合面包团，用胃模拟器（HGS）消化，在有无纯化菠萝蛋白酶的情况下消化。胃消化进行 150 分钟，在不同时间点排空胃液。排空的样品立即在模拟小肠条件下消化。收集胃和小肠等分试样，以定量分析肽谱和 9 种标记免疫原性肽（分别通过非靶向和靶向质谱法）、R5 表位（通过基于单克隆抗体的竞争测定法）以及消化过程中释放的游离氨基（通过 -邻苯二醛法）。菠萝蛋白酶和消化时间对小麦蛋白的水解和该材料中面筋 R5 表位排空 HGS 的量有显著影响（<0.05）。菠萝蛋白酶在消化的前 20 分钟加速了小麦蛋白的胃水解，这反映在 R5 表位的更快减少（5.5μgmin）。菠萝蛋白酶加速了（<0.05）大多数免疫原性标记肽的消失率。例如，在小肠消化的前 20 分钟内，存在菠萝蛋白酶时，33 肽的减少速度（<0.05）加快了 2 倍（0.25. 0.12μg g 面包/分钟）。非靶向肽组学研究表明，菠萝蛋白酶减少了模拟小肠消化中已知免疫原性肽的含量。这些发现表明，在口腔-胃肠道联合消化模型中，菠萝蛋白酶加速了常见食物基质（面包）中小麦蛋白和已知面筋免疫原性肽的水解。
