State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China.
National R&D Branch Center for Conventional Freshwater Fish Processing, Jiangxi Normal University, Nanchang, Jiangxi 330022, People's Republic of China.
J Agric Food Chem. 2021 Jun 23;69(24):6850-6859. doi: 10.1021/acs.jafc.1c02205. Epub 2021 Jun 11.
Physical-assisted chemical modification is effective to reduce the allergenicity of α-lactalbumin (ALA). However, there are few in-depth studies on the allergenicity changes of physical-assisted chemical-modified ALA during digestion. The effect of gastroduodenal digestion on the allergenicity changes of ALA treated by sonication-assisted glycation was assessed. Digestion of both ALA and its glycated forms generated peptide fractions, and intact undigested glycated ALA in the hydrolysates still covalently bound to d-galactose. High-resolution mass spectrometry revealed that a higher glycation degree was discovered in sonication-preprocessed ALA compared to native ALA. Enzyme-linked immunosorbent assay and basophil degranulation showed that sonication-assisted glycation could significantly reduce ALA allergenicity. The allergenicity of both gastric and gastroduodenal hydrolysates was further increased, and the hydrolysates of sonication-assisted glycated ALA showed the lowest allergenicity. The reason could be the shielding effect of the linear epitope found to be caused by a higher glycation degree; although linear epitopes were exposed, d-galactose covalently bound to intact undigested glycated ALA in the hydrolysates retained its masking role. These results indicated that sonication-assisted glycation could be a promising method to prepare immunotherapeutic agents for allergen immunotherapy to achieve the purpose of allergy desensitization.
物理辅助化学修饰可有效降低α-乳白蛋白（ALA）的致敏性。然而，关于物理辅助化学修饰的 ALA 在消化过程中致敏性变化的深入研究较少。本研究评估了超声辅助糖化处理的 ALA 在胃十二指肠消化过程中致敏性变化。ALA 及其糖化形式的消化均产生肽片段，且水解物中未消化的完整糖化 ALA 仍与 d-半乳糖共价结合。高分辨质谱揭示，与天然 ALA 相比，超声预处理的 ALA 具有更高的糖化程度。酶联免疫吸附试验和嗜碱性粒细胞脱颗粒实验表明，超声辅助糖化可显著降低 ALA 的致敏性。胃和胃十二指肠水解物的致敏性进一步增加，超声辅助糖化 ALA 的水解物具有最低的致敏性。原因可能是由于更高的糖化程度导致线性表位的屏蔽效应；尽管线性表位暴露，但水解物中与完整未消化的糖化 ALA 共价结合的 d-半乳糖仍保留其掩蔽作用。这些结果表明，超声辅助糖化可能是制备变应原免疫治疗剂用于变应原免疫治疗以实现过敏脱敏目的的有前途的方法。
