糖基化改性对大豆蛋白抗原性及结构特性的影响研究.doc

糖基化改性对大豆蛋白抗原性及结构特性的影响研究 布冠好 朱婷伟 陈复生( （河南工业大学粮油食品学院，郑州 450001） 摘要 本文以大豆分离蛋白和葡聚糖为原料，在干热条件下进行美拉德反应，制取不同时间下的糖基化复合物。以β-伴大豆球蛋白和大豆球蛋白抗原抑制率为指标，采用间接竞争ELISA方法测定糖基化产物的抗原性，在反应6 d时，糖基化产物中β-伴大豆球蛋白和大豆球蛋白的抗原性分别降低了31.94%和21.26%。糖基化产物颜色加深，且游离氨基含量降低，说明大豆蛋白与糖发生了不同程度的反应。红外光谱中糖链的引入，使蛋白质分子展开，β-转角和无规则卷曲结构含量降低，影响了β-伴大豆球蛋白α亚基的抗原表位，从而可能使大豆蛋白的抗原性降低。糖基化反应影响抗原性的关键作用在于蛋白与糖结合部位对蛋白质结构变化的影响。 关键词 大豆分离蛋白 葡聚糖 糖基化 抗原性 结构 中图分类号：TS21 文献标识码：A Effects of glycation modification on soybean protein antigenicity and structural properties Guanhao Bu, Tingwei Zhu, Fusheng Chen* College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China Abstract Soy protein isolate (SPI) and dextran were used as raw materials and SPI-dextran conjugate were prepared under dry-heated at different times through Maillard reaction in this paper. The antigen inhibition rate of β-conglycinin and glycinin in SPI-dextran conjugate were tested with indirect competitive ELISA method. The antigenicity of β-conglycinin and glycinin decreased 31.94% and 21.26% respectively when the reaction processed at 6 days. Meanwhile, the color deepened and the free amino group content reduced which indicated that different degrees of reaction occurred between soy protein isolate with dextran. FTIR indicated that the protein structure of glycated samples unfolded as the introduced sugar chains. The reduced β-corner and random coil structure content impacted the epitope of β-conglycinin antigen in soybean protein, and then reduced the antigenicity of soybean protein. These showed that the key effect relies on the structure changes caused by the binding site between protein and saccharide. Keywords Soybean protein isolate, Dextran, Glycation, Antigenicity, Structures 大豆作为一种优质的植物蛋白来源，被广泛应用于食品以及饲料工业中。大豆中的蛋白质营养价值高且价格相对廉价，但大豆蛋白也是常见的8大食物蛋白过敏原之一。大豆分离蛋白（SPI）是一种蛋白质含量不低于90%的大豆产品，其主要成分包括大豆球蛋白与β-伴大豆球蛋白[1]。β-伴大豆球蛋白是7S的主要组成，是由3个亚基α（~67 ku）、α′（~71 ku）、β（~50 ku）组成的三聚体[2]。大豆球蛋白作为11S的主要组分，是一个六聚体蛋白质，每个亚基单位均含有一个酸性链和碱性链，并通过二硫键