Effective reduction of the allergenicity of instant soy milk powder (ISMP) is practically valuable for expanding its applications. This study optimized the enzymolysis technology of ISMP using single-factor experiments and response surface methodology, combined serological analysis, cellular immunological models, bioinformatics tools, and multiple spectroscopy techniques to investigate the effects of alcalase hydrolysis on allergenicity, spatial conformation, and linear epitopes of ISMP. Under the optimal process, special IgE and IgG1 binding abilities and allergenic activity to induce cell degranulation of alcalase-hydrolyzed ISMP were reduced by (64.72 ± 1.76)%, (56.79 ± 3.72)%, and (73.3 ± 1.19)%, respectively (P < 0.05). Moreover, the spatial conformation of instant soy milk powder hydrolysates (ISMPH) changed, including decreased surface hydrophobicity, a weaker peak of amide II band, lower contents of α-helix and β-sheet, and an enhanced content of random coil. Furthermore, the linear epitopes of major soy allergens, 9 from glycinin and 13 from β-conglycinin, could be directionally disrupted by alcalase hydrolysis. Overall, the structure–activity mechanism of alcalase hydrolysis to reduce ISMP allergenicity in vitro was preliminarily clarified. It provided a new research direction for the breakthrough in the desensitization of ISMP and a theoretical basis for revealing the potential mechanism of alcalase enzymolysis to reduce the allergenicity of ISMP.

中文翻译：

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Alcalase水解降低速溶豆奶粉体外致敏性的构象活性机制

有效降低速溶豆奶粉（ISMP）的致敏性对于扩大其应用具有实际价值。本研究采用单因素实验和响应面法优化ISMP酶解工艺，结合血清学分析、细胞免疫模型、生物信息学工具和多重光谱技术，研究碱性酶水解对ISMP致敏性、空间构象和线性表位的影响。 ISMP。在最佳工艺下，Alcalase水解ISMP的特殊IgE和IgG1结合能力和诱导细胞脱粒的致敏活性分别降低了（64.72±1.76）％、（56.79±3.72）％和（73.3±1.19）％（P <0.05）。此外，速溶豆奶粉水解物（ISMPH）的空间构象发生了变化，包括表面疏水性降低、酰胺II带峰变弱、α-螺旋和β-折叠含量降低、无规卷曲含量增加。此外，主要大豆过敏原的线性表位（9 个来自大豆球蛋白，13 个来自β-伴大豆球蛋白）可以被碱性酶水解定向破坏。总体而言，初步阐明了碱性酶水解降低ISMP体外致敏性的构效机制。为ISMP脱敏的突破提供了新的研究方向，也为揭示Alcalase酶解降低ISMP致敏性的潜在机制提供了理论基础。