Gianfrani Carmen, Mamone Gianfranco, la Gatta Barbara, Camarca Alessandra, Di Stasio Luigia, Maurano Francesco, Picascia Stefania, Capozzi Vito, Perna Giuseppe, Picariello Gianluca, Di Luccia Aldo
Institute of Protein Biochemistry, CNR, Naples, Italy.
Institute of Food Sciences, CNR Avellino, Italy.
Food Chem Toxicol. 2017 Mar;101:105-113. doi: 10.1016/j.fct.2017.01.010. Epub 2017 Jan 12.
Microwave based treatment (MWT) of wet wheat kernels induced a striking reduction of gluten, up to <20 ppm as determined by R5-antibodybased ELISA, so that wheat could be labeled as gluten-free. In contrast, analysis of gluten peptides by G12 antibody-based ELISA, mass spectrometry-based proteomics and in vitro assay with T cells of celiac subjects, indicated no difference of antigenicity before and after MWT. SDS-PAGE analysis and Raman spectroscopy demonstrated that MWT simply induced conformational modifications, reducing alcohol solubility of gliadins and altering the access of R5-antibody to the gluten epitopes. Thus, MWT neither destroys gluten nor modifies chemically the toxic epitopes, contradicting the preliminary claims that MWT of wheat kernels detoxifies gluten. This study provides evidence that R5-antibody ELISA alone is not effective to determine gluten in thermally treated wheat products. Gluten epitopes in processed wheat should be monitored using strategies based on combined immunoassays with T cells from celiacs, G12-antibody ELISA after proteolysis and proper molecular characterization.
基于微波的湿小麦粒处理（MWT）可使面筋显著减少，基于R5抗体的酶联免疫吸附测定（ELISA）测定结果显示面筋含量降至<20 ppm，从而使小麦可被标记为无麸质。相比之下，基于G12抗体的ELISA、基于质谱的蛋白质组学以及对乳糜泻患者T细胞的体外检测对面筋肽进行分析，结果表明MWT前后抗原性并无差异。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析和拉曼光谱表明，MWT仅诱导了构象修饰，降低了醇溶蛋白的醇溶性，并改变了R5抗体与面筋表位的结合。因此，MWT既不会破坏面筋，也不会对有毒表位进行化学修饰，这与之前关于小麦粒MWT可使面筋解毒的初步说法相矛盾。本研究提供了证据，表明仅用R5抗体ELISA无法有效测定热处理小麦制品中的面筋。对于加工小麦中的面筋表位，应采用基于联合免疫检测（使用来自乳糜泻患者的T细胞）、蛋白水解后的G12抗体ELISA以及适当的分子表征等策略进行监测。
