Department of Nutritional Medicine/Prevention, University of Hohenheim, Fruwirthstrasse 12, Stuttgart 70593, Germany.
Core Facility Hohenheim, Mass Spectrometry Module, University of Hohenheim, August-von-Hartmann-Strasse 3, 70599 Stuttgart, Germany.
J Proteomics. 2021 Sep 15;247:104318. doi: 10.1016/j.jprot.2021.104318. Epub 2021 Jul 3.
BACKGROUND/OBJECTIVES: Cereal products like flour and bread are known to trigger diseases such as wheat allergy, celiac disease and non-celiac wheat sensitivity (NCWS). Some of these diseases are caused by allergenic proteins, the expression of which might vary depending on the grain type and manufacturing processes. Therefore, we examined the protein composition and abundance of potentially allergenic proteins in flours from bread wheat, spelt and rye, and corresponding breads.
Using Nano-LC-ESI-MS/MS and label free quantification (LFQ) we analyzed the proteome of six different bread flours (wholegrain and superfine flours from rye, spelt and bread wheat) and 14 bread types (yeast and sourdough fermented breads from all flours and wheat breads plus/minus bread improver). Potentially allergenic proteins in flours and breads were functionally categorized using the Pfam database and relatively quantified by LFQ.
We could show that almost equal numbers of proteins can be identified in rye- and spelt samples compared to wheat samples using the Uniprot bread wheat protein database, indicating high sequence conservation between cereals. In total, 4424 proteins were identified in the 20 flour and bread samples. The average number of identified proteins in flour (2719 ± 243) was slightly higher than in bread (2283 ± 232; P < 0.001). In wheat- and spelt wholegrain flour higher protein numbers (wheat: 2891 ± 90; spelt: 2743 ± 140) were identified on average than in superfine flour (wheat: 2562 ± 79; P = 0.009; spelt: 2431 ± 140; P = 0.004). Neither the absolute number nor the abundance distribution of potentially allergenic proteins were dependent on the flour type or the fermentation process, but known allergenic proteins like gliadins showed higher relative abundance in spelt- and wheat samples, compared to rye samples.
We provide comprehensive proteome data for six flour types and related breads showing that the grain species have greater influence on proteome composition than milling and fermentation processes. Our data indicate that allergenic proteins are not selectively degraded during bread production and are more abundant in bread wheat and spelt compared to rye.
Our proteomics study revealed that bread contains a number of potentially and proven allergenic proteins. Most likely allergenicity is not dependent on milling or conventional fermentation processes, but on the grain type. Relative abundance of allergenic proteins was higher in spelt- and wheat samples than in rye samples. Considering rye bread as better suited to atopic individuals predisposed to react to cereal allergens, clinical trials are warranted to verify this assumption.
背景/目的：面粉和面包等谷物产品已知会引发小麦过敏、乳糜泻和非乳糜泻小麦敏感（NCWS）等疾病。其中一些疾病是由过敏原蛋白引起的，其表达可能因谷物类型和制造工艺而异。因此，我们研究了面包小麦、斯佩耳特小麦和黑麦的面粉以及相应面包中潜在致敏蛋白的蛋白质组成和丰度。
使用纳升液相色谱-电喷雾-串联质谱（Nano-LC-ESI-MS/MS）和无标记定量（LFQ）技术，我们分析了六种不同面包粉（黑麦、斯佩耳特小麦和面包小麦的全麦粉和超细粉）和 14 种面包（所有面粉的酵母和酸面团发酵面包以及加/不加面包改良剂的小麦面包）的蛋白质组。使用 Pfam 数据库对面粉和面包中的潜在致敏蛋白进行功能分类，并通过 LFQ 进行相对定量。
我们发现，使用 Uniprot 面包小麦蛋白质数据库，与小麦样品相比，黑麦和斯佩耳特小麦样品中可鉴定的蛋白质数量几乎相同，这表明谷物之间具有很高的序列保守性。在 20 个面粉和面包样品中总共鉴定到 4424 种蛋白质。面粉中鉴定到的蛋白质平均数量（2719 ± 243）略高于面包（2283 ± 232；P < 0.001）。在全麦面粉中，黑麦（2891 ± 90）和斯佩耳特小麦（2743 ± 140）的平均蛋白质数量高于超细面粉（黑麦：2562 ± 79；P = 0.009；斯佩耳特小麦：2431 ± 140；P = 0.004）。潜在致敏蛋白的绝对数量或丰度分布既不依赖于面粉类型，也不依赖于发酵过程，但已知的致敏蛋白，如麦醇溶蛋白，在斯佩耳特小麦和小麦样品中的相对丰度高于黑麦样品。
我们提供了六种面粉类型及其相关面包的综合蛋白质组数据，表明谷物种类对蛋白质组组成的影响大于研磨和发酵过程。我们的数据表明，致敏蛋白在面包生产过程中不会被选择性降解，并且在小麦和斯佩耳特小麦中的含量高于黑麦。
我们的蛋白质组学研究表明，面包中含有许多潜在和已证实的致敏蛋白。致敏性很可能不依赖于研磨或传统发酵过程，而是取决于谷物类型。在斯佩耳特小麦和小麦样品中的相对丰度高于黑麦样品。鉴于黑麦面包更适合对谷物过敏原有过敏反应倾向的特应性个体，有必要进行临床试验来验证这一假设。
