食品科学 ›› 2020, Vol. 41 ›› Issue (18): 51-57.doi: 10.7506/spkx1002-6630-20190716-222

• 食品化学 • 上一篇    下一篇

pH值对米糠清蛋白和球蛋白的结构、溶解性及表面疏水性的影响

杨健,富天昕,张舒,冯玉超,王长远   

  1. (1.国家杂粮工程技术研究中心,黑龙江?大庆 163319;2.黑龙江八一农垦大学食品学院,黑龙江?大庆 163319)
  • 出版日期:2020-09-25 发布日期:2020-09-18
  • 基金资助:
    黑龙江省自然科学基金项目(LH2019C054);黑龙江省博士后基金项目(LBH-Z15217); 黑龙江省农垦总局科技项目(HNK135-05-01);“十三五”国家科技支撑计划项目(2017YFD0401203)

Effect of pH on the Structure, Solubility and Surface Hydrophobicity of Albumin and Globulin from Rice Bran

YANG Jian, FU Tianxin, ZHANG Shu, FENG Yuchao, WANG Changyuan   

  1. (1. National Coarse Cereals Engineering Research Center, Daqing 163319, China; 2. College of Food Science, Heilongjiang Bayi Agricultural University, Daqing 163319, China)
  • Online:2020-09-25 Published:2020-09-18

摘要: 为解决米糠蛋白提取率低、产品功能性质不佳的问题,以达到增加米糠蛋白利用率的目的。本实验基于蛋白质化学理论和谱学分析技术等探究pH值对米糠清蛋白和球蛋白结构、溶解性及表面疏水性的影响。结果表明:随着pH值的增加,米糠清蛋白、球蛋白的流体动力学直径分布均呈降低趋势,Zeta电位绝对值均呈增大的趋势;米糠清蛋白中α-螺旋结构的含量逐渐增大,而β-折叠结构含量则逐渐减小,无规卷曲结构含量逐渐增大;米糠清蛋白和球蛋白的色氨酸残基趋近于“暴露”态。因此,碱性条件下,米糠球蛋白保留了大部分二级结构、亚基解离诱导的蛋白质三级结构解折叠是其表面疏水性小幅提高的主要原因;米糠清蛋白的二级结构单元的无序性转变、亚基解离诱导的蛋白结构解折叠,是其表面疏水性增大的原因;亚基解离成小粒径以及碱性条件赋予米糠蛋白电荷,是米糠清蛋白及球蛋白溶解性增加的重要原因。

关键词: pH值;米糠蛋白;结构;溶解性;表面疏水性

Abstract: The purpose of this study was to solve the problem of low extraction rate of rice bran protein and poor product functions and properties in order to increase the utilization rate of rice bran protein. The effects of pH on the structure, solubility and surface hydrophobicity of rice bran albumin and globulin were investigated based on the theory of protein chemistry and spectroscopic analysis. The results showed that with the increase in pH, the hydrodynamic diameter distribution of rice bran albumin and globulin followed a declining trend while the zeta potential absolute value exhibited an increasing trend. The content of α-helix and random coil structure in rice bran albumin increased gradually, while the content of β-fold structure decreased gradually. Tryptophan residues of rice bran albumin and globulin tended to be “exposed”. In conclusion, under alkaline conditions, rice bran globulin remained most of its secondary structures and subunit dissociation induced the tertiary structure of the protein, which was the main reason for the increase in the surface hydrophobicity. As for rice bran albumin, the transformation of secondary structural units from an ordered to a disordered state and subunit dissociation-induced protein unfolding were the reason for the increase in the surface hydrophobicity. The increase in the solubility of rice bran albumin and globulin was accounted for by the fact that the subunits were dissociate into small particles and the protein particles were charged under alkaline conditions.

Key words: pH; rice bran protein; structure; solubility; surface hydrophobicity

中图分类号: