食品科学 ›› 2019, Vol. 40 ›› Issue (16): 58-63.doi: 10.7506/spkx1002-6630-20190117-198

• 食品化学 • 上一篇    下一篇

大豆分离蛋白酶促聚集行为的表征

曾 祺,张志国   

  1. 齐鲁工业大学(山东省科学院)食品科学与工程学院,山东 济南 250353
  • 出版日期:2019-08-25 发布日期:2019-08-26
  • 基金资助:
    山东省自然科学基金面上项目(ZR2016CM38)

Characterization of the Enzyme-Induced Aggregation Behavior of Soybean Protein Isolate

ZENG Qi, ZHANG Zhiguo   

  1. College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
  • Online:2019-08-25 Published:2019-08-26

摘要: 研究Quambalaria cyanescens天冬氨酸蛋白酶处理后大豆分离蛋白(soybean protein isolate,SPI)的水解度、浊度、组分及分子质量变化,利用激光扫描共聚焦显微镜(laser scanning confocal microscopy,LSCM)和原子力显微镜(atomic force microscope,AFM)表征酶处理后大豆分离蛋白聚集行为。结果表明:SPI水解度、浊度在一定范围内随酶解时间的延长而增加,随后保持不变;酶处理使SPI的亚基解离,水解为较小分子质量的组分,并使SPI表面疏水性增强;内源荧光光谱与圆二色光谱结果表明酶解改变了SPI的天然结构,导致SPI内部氨基酸残基及疏水基团的暴露。通过LSCM观察酶诱导的SPI聚集过程,结合AFM的观察结果表明:随处理时间的延长,SPI发生了更广泛的聚集行为,并产生了更大的不规则、不连续聚集体。

关键词: 大豆分离蛋白, 酶处理, 结构特性, 聚集行为

Abstract: The changes in the degree of hydrolysis (DH), turbidity, components and molecular mass, surface hydrophobicity and structure of soybean protein isolate (SPI) were studied after being treated with an aspartic protease (AP) from Quambalaria cyanescens. The enzyme-induced aggregation behavior of SPI was determined by laser scanning confocal microscopy (LSCM) and atomic force microscopy (AFM). The results indicated that the DH and turbidity of SPI increased first and then tended to be stable with the increase of AP treatment time. The enzymatic treatment caused subunit dissociation of SPI, leading to its hydrolysis into smaller molecules. This treatment also increased the surface hydrophobicity of SPI. The circular dichroism (CD) spectrum and intrinsic fluorescence emission spectrum of SPI showed that the enzymatic treatment significantly changed its structure, causing the exposure of internal hydrophobic groups and hydrophobic amino acid residues. LSCM and AFM observation showed that the increases of enzymatic treatment time caused more extensive aggregation of SPI, resulting in the formation of bigger, irregular and discontinuous aggregates.

Key words: soybean protein isolate, enzymatic treatment, structural characterization, aggregation behavior

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