γ射线辐照对小麦粉面筋蛋白结构及 功能特性的影响研究

Effect of γ-irradiation on Functional Properties and Structure of Wheat Gluten Protein

采用不同剂量的^(60)Co-γ射线辐照(0、5、10、15、20、25kGy)处理小麦粉,研究辐照对其面筋蛋白的结构和功能特性的影响。结果表明:辐照使面筋蛋白二硫键断裂,游离巯基含量增加。傅里叶变换红外光谱表明,辐照导致α-螺旋含量降低、β-折叠含量增加,使面筋蛋白的二级结构发生了重排。拉曼光谱和表面疏水性的观测结果表明,芳香族氨基酸侧链的微环境发生了变化,经过辐照处理,色氨酸和酪氨酸残基更趋于暴露态,表面疏水性增强。辐照处理提高了面筋蛋白的溶解度、持水性、持油性及乳化性,在15kGy处理时达到最大值(溶解度0.46 mg/mL,持水性3.13g/g,持油性4.33 g/g,乳化活性6.669 m^(2)/g)。综上所述,适当剂量的γ射线辐照处理可以改变面筋蛋白的二级、三级结构,并改善其溶解性、持水性和乳化性等功能特性,有利于拓展面筋蛋白的应用空间,为其在食品工业上的应用提供理论指导。

In this paper,wheat flour was irradiated at different doses(0,5,10,15,20 and 25 kGy)to investigate the effects of ^(60)Co-γirradiation on the structural and functional properties of its gluten.The disulfide bond was broken by irradiation,and the content of the free sulfhydryl group increased.The results of Fourier infrared spectroscopy showed that the secondary structure of gluten protein was rearranged with decrease in a-helix content and an increase inβ-sheet content.Raman spectroscopy and surface hydrophobicity showed that the microenvironment of aromatic amino acid side chains changed.Irradiation treatment resulted in the tryptophan and tyrosine residues tending more toward the exposed state,and the surface hydrophobicity increased.Meanwhile,irradiation increased the solubility,water and oil holding,and emulsifying properties of gluten proteins,and the maximum value reached at 15 kGy(solubility is 0.46 mg/mL,water holding 3.13 g/g,oil holding 4.33 g/g,emulsification 6.669 m^(2)/g).In conclusion,the proper dose of gamma-irradiation can change the secondary and tertiary structure of gluten,and improve its functional properties such as solubility,water retention and emulsification,which is conducive to expanding the application space of gluten protein and providing theoretical references for industrial applications.