Abstract：
Lactic acid bacterial fermentation helps reduce the immunoreactivity of soy protein. Nevertheless, the effect of lactic acid bacterial fermentation on a particular soy allergen and the consequent dynamic change of epitopes during gastrointestinal digestion are unclear. In this study, soy glycinin was isolated and an in vitro dynamic gastrointestinal model was established to investigate the dynamic change in the immunoreactivity and peptide profile of unfermented (UG) and fermented glycinin (FG) digestates. The results demonstrated that the FG intestinal digestate had a lower antigenicity (0.08%-0.12%) and IgE-binding capacity (1.49%-3.61%) towards glycinin at the early (I-5) and middle (I-30) stages of gastrointestinal digestion, especially those prepared at 2% (w/v) protein concentration. Peptidomic analysis showed that the glycinin subunits G1 and G2 were the preferred ones to release the most abundant peptides, whereas G2, G4, and G5 had an elevated epitope-cleavage rate in FG at stages I-5 and I-30. Three-dimensional modeling revealed that fermentation-induced differential degradation epitopes in gastrointestinal digestion were predominantly located in the α-helix and β-sheet structures. They were closely correlated with the reduced immunoreactivity of soy glycinin.
摘要：
乳酸菌发酵有助于降低大豆蛋白的免疫反应性。然而，乳酸菌发酵对特定大豆过敏原的影响以及胃肠道消化过程中表位的动态变化尚不清楚。在这项研究中,分离大豆大豆球蛋白，并建立体外动态胃肠模型，以研究未发酵（UG）和发酵大豆球蛋白（FG）消化物的免疫反应性和肽谱的动态变化。结果表明，在胃肠道消化的早期（I-5）和中期（I-30）阶段，FG肠消化产物对大豆球蛋白具有较低的抗原性（0.08％-0.12％）和IgE结合能力（1.49％-3.61％）。特别是那些在2％（w/v）蛋白质浓度制备。肽分析显示大豆球蛋白亚基G1和G2是释放最丰富肽的首选亚基，而G2，G4和G5在I-5和I-30阶段的FG中具有升高的表位切割率。三维建模显示，胃肠道消化中发酵诱导的差异降解表位主要位于α-螺旋和β-折叠结构中。它们与大豆大豆球蛋白的免疫反应性降低密切相关。
