Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Division of Mechatronics, Biostatistics and Sensors (MeBioS), KU Leuven, Kasteelpark Arenberg 30, B-3001 Leuven, Belgium.
J Agric Food Chem. 2021 Feb 17;69(6):1963-1974. doi: 10.1021/acs.jafc.0c05868. Epub 2021 Feb 5.
Formation of amyloid fibrils (., protein structures containing a compact core of ordered β-sheet structures) from food proteins can improve their techno-functional properties. Wheat gluten is the most consumed cereal protein by humans and extensively present in food and feed systems. Hydrolysis of wheat gluten increases the solubility of its proteins and brings new opportunities for value creation. In this study, the formation of amyloid-like fibrils (ALFs) from wheat gluten peptides (WGPs) under food relevant processing conditions was investigated. Different hydrothermal treatments were tested to maximize the formation of straight ALFs from WGPs. Thioflavin T (ThT) fluorescence measurements and transmission electron microscopy (TEM) were performed to study the extent of fibrillation and the morphology of the fibrils, respectively. First, the formation of fibrils by heating solutions of tryptic WGPs [degrees of hydrolysis 2.0% (DH 2) or 6.0% (DH 6)] was optimized using a response surface design. WGP solutions were incubated at different pH values, times, and temperatures. DH 6 WGPs had a higher propensity for fibrillation than did DH 2 WGPs. Heating DH 6 WGPs at 2.0% (w/v) for 38 h at 85 °C and pH 7.0 resulted in optimal fibrillation. Second, trypsin, chymotrypsin, thermolysin, papain, and proteinase K were used to produce different DH 6 WGPs. After enzyme inactivation and subsequent heating at optimal fibrillation conditions, chymotrypsin and proteinase K DH 6 WGPs produced small worm-like fibrils, whereas fibrils prepared from trypsin DH 6 WGPs were long and straight. The surface hydrophobicity of the peptides was key for fibrillation. Third, peptides from the wheat gluten components gliadin and glutenin fractions formed smaller and worm-like fibrils than did WGPs. Thus, the peptides of both gluten protein fractions jointly contribute to gluten fibrillation.
在食品相关加工条件下，从小麦面筋蛋白（WP）制备具有典型纤维形态的蛋白聚集体。小麦面筋是人类最常食用的谷物蛋白，广泛存在于食品和饲料系统中。小麦面筋蛋白的水解增加了其蛋白质的溶解性，并为创造新的价值带来了新的机会。本研究探讨了在食品相关加工条件下，从小麦面筋蛋白肽（WGPs）中形成类似淀粉样纤维（ALFs）的情况。测试了不同的湿热处理方法，以最大限度地从 WGPs 中制备直的 ALFs。使用硫黄素 T（ThT）荧光测量和透射电子显微镜（TEM）分别研究了纤维的形成程度和纤维的形态。首先，通过使用响应面设计优化了加热胰蛋白酶 WGPs[水解度（DH）2.0%（DH 2）或 6.0%（DH 6）]溶液中纤维的形成。将 WGP 溶液在不同的 pH 值、时间和温度下孵育。DH 6 WGPs 的纤维形成倾向高于 DH 2 WGPs。在 85°C 和 pH 7.0 下，以 2.0%（w/v）加热 DH 6 WGPs 38 h 可获得最佳的纤维形成。其次，使用胰蛋白酶、糜蛋白酶、嗜热菌蛋白酶、木瓜蛋白酶和蛋白酶 K 制备不同的 DH 6 WGPs。酶失活后，在最佳纤维形成条件下加热，糜蛋白酶和蛋白酶 K DH 6 WGPs 产生小的蠕虫状纤维，而从胰蛋白酶 DH 6 WGPs 制备的纤维则又长又直。肽的表面疏水性是纤维形成的关键。第三，来自小麦面筋成分醇溶蛋白和麦谷蛋白组分的肽形成的纤维比 WGPs 小且呈蠕虫状。因此，两种面筋蛋白组分的肽都共同促成了面筋的纤维形成。
