"挤压膨化温度对大豆分离蛋白抗原性 及结构的影响""Effect of extrusion temperature on antigenicity and structure of soybean protein isolate"

旨在为开发大豆蛋白的脱敏技术提供参考，对大豆分离蛋白（SPI）进行挤压膨化处理，对不同挤压膨化温度下SPI的抗原性、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）、氨基酸组成、溶解度、紫外吸收光谱、内源荧光光谱及表面疏水性进行分析。结果表明：随着挤压膨化温度的升高，SPI抗原性呈现先降低再升高的趋势，145 ℃时SPI的抗原性下降最为显著；SPI中抗原蛋白β-伴大豆球蛋白的α、α′、β亚基以及大豆球蛋白的酸性亚基和碱性亚基均发生明显降解；SPI的氨基酸组成、必需氨基酸含量与氨基酸总量比值无明显变化，营养性保持良好；SPI溶解度降低；氢键、二硫键、疏水相互作用均是维持SPI空间结构的分子作用力，其中氢键起主要作用；SPI的紫外光谱和内源荧光光谱均出现不同程度的红移，紫外吸收强度及荧光强度发生变化，表面疏水性显著下降，SPI的三级结构发生改变。综上，挤压膨化能够在一定程度上降低SPI的抗原性，并影响其空间结构。 In order to provide reference for the development of desensitization technology of soybean protein, the antigenicity, SDS-PAGE, amino acid composition, solubility, UV absorption spectra, endogenous fluorescence spectra and surface hydrophobicity of the soybean protein isolate (SPI) extruded at different extrusion temperatures. The results showed that the antigenicity of SPI decreased first and then increased with the increase of extrusion temperature, and the antigenicity of SPI decreased most significantly at 145 ℃. The α, α′ and β subunits of the antigen protein β-conglycinin and the acidic and basic subunits of glycinin in SPI were significantly degraded. The amino acid composition and the ratio of essential amino acids to total amino acids of SPI had no obvious change, and the nutritional characteristics of SPI remained good. After extrusion, the solubility of SPI decreased, and hydrogen bond, disulfide bond and hydrophobic interaction were the molecular forces that maintained SPI spatial structure, in which hydrogen bond played the main role. The UV and endogenous fluorescence spectra of SPI extruded showed different degrees of redshift, the UV absorption intensity and fluorescence intensity changed, the surface hydrophobicity decreased significantly, and the tertiary structure of SPI changed. In conclusion, extrusion can reduce the antigenicity of SPI to a certain extent and affect its spatial structure.