食品科学 ›› 2018, Vol. 39 ›› Issue (14): 22-28.doi: 10.7506/spkx1002-6630-201814004

• 食品化学 • 上一篇    下一篇

pH偏移结合热处理对大豆蛋白柔性与乳化性的影响

王健,徐晔晔,于洁,高婷婷,王喜波*,江连洲   

  1. (东北农业大学食品学院,黑龙江?哈尔滨 150030)
  • 出版日期:2018-07-25 发布日期:2018-07-16
  • 基金资助:
    现代农业(大豆)产业技术体系建设专项(CARS-04-PS28)

Effect of pH-Shifting Combined with Heat Treatment on the Flexibility and Emulsifying Properties of Soy Protein Isolate

WANG Jian, XU Yeye, YU Jie, GAO Tingting, WANG Xibo*, JIANG Lianzhou   

  1. (College of Food Science, Northeast Agricultural University, Harbin 150030, China)
  • Online:2018-07-25 Published:2018-07-16

摘要: 研究pH偏移(pH?7.0、pH?2.0、pH?11.0)结合热处理(90、120?℃)对大豆分离蛋白(soy?protein?isolate,SPI)柔性的影响,并探索SPI柔性与结构和乳化性质的关系。结果表明,在各个pH偏移处理条件下,SPI柔性随着处理温度的升高而增加。相比于pH?7.0条件下,pH?2.0和pH?11.0偏移处理促进了SPI在加热过程中柔性的增加,其中pH?11.0条件下热处理对柔性影响更加强烈。pH?7.0条件下,游离巯基浓度随热处理温度的升高而增加,SPI柔性的增加与SPI内二硫键的断裂有关。pH?11.0偏移处理条件下,SPI在加热过程中发生了解离,SPI柔性增加。在实验条件下,SPI柔性与乳化活性和乳化稳定性呈显著正相关,相关系数分别为0.945和0.936。紫外扫描、内源性色氨酸荧光光谱研究发现随着柔性的增加,SPI结构变的更加舒展。

关键词: pH偏移, 热处理, 大豆分离蛋白, 柔性, 乳化性质

Abstract: The effect of pH-shifting (pH 7.0, 2.0, and 11.0) combined with heat treatment (90 and 120 ℃) on the flexibility of soy protein isolate (SPI) and the relationships between flexibility and structure or emulsifying properties were investigated. The results suggest that the flexibility of SPI was increased with heating temperature under different pH-shifting treatment conditions. pH-shifting treatment from 2.0 or 11.0 to 7.0 contributed to the increased flexibility of SPI during heating as compared with that at pH 7.0. The heat treatment increased the flexibility more significantly at pH 11.0. At pH 7.0, the content of free sulfhydryl group was increased with heating temperature, indicating that the increase in the flexibility was related to the cleavage of the disulfide bond of SPI. Under pH-shifting treatment from 11.0, the dissociation of the SPI molecule occurred during the heating process, thereby increasing the flexibility. Under the experimental conditions, the flexibility showed a significantly positive correlation with the emulsifying activity and emulsion stability, with correlation coefficients of 0.945 and 0.936, respectively. UV spectroscopy and endogenous tryptophan fluorescence spectroscopy suggested that the SPI structure became more unfolded as the flexibility increased.

Key words: pH-shifting, heat treatment, soy protein isolate, flexibility, emulsifying properties

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