高压均质对大豆蛋白柔性和乳化性的影响及相关性分析

以大豆分离蛋白(Soy protein isolate,SPI)对胰蛋酶的敏感性表征其柔性,研究不同均质压力(0~200 MPa)对SPI柔性和乳化性的影响,并探索SPI结构变化及其柔性与乳化性之间的相关性。结果表明,当均质压力为0~160 MPa时,SPI柔性随着均质压力的增加而增加,160~180 MPa时柔性变化不明显,当均质压力为180~200 MPa时,SPI柔性又呈现下降的趋势。表面疏水性随着均质压力的增大而增大,而浊度则随之减小,柔性随均质压力的变化趋势与乳化性随均质压力的变化趋势一致。相关性分析结果表明:SPI柔性与乳化活性和乳化稳定性呈线性正相关关系,相关系数分别为0.893和0.938。紫外扫描、内源性色氨酸荧光光谱研究发现,随着SPI柔性的增加,其结构变得更加舒展。

Effect of High Pressure Homogenization on Flexibility and Emulsifying Properties of Soy Protein Isolate and Correlation Analysis

The sensitivity of soy protein isolate to trypsin was characterized by its flexibility. The effects of different homogenization pressures (0~200MPa) on soy protein isolate flexibility and emulsifying properties were investigated. The changes of soy protein isolate structure and the correlation analysis between flexibility and emulsifying properties (emulsifying activity and emulsion stability) were also investigated. The results showed that when the homogenization pressure was 0~160MPa, the soy protein isolate flexibility was increased with the increase of the homogenization pressure, while the flexibility did not change obviously at 160~180MPa. When the homogenization pressure was 180~200MPa, the soy protein isolate flexibility was declined. The surface hydrophobicity was increased with the increase of homogeneous pressure, while the turbidity was decreased. The changing tendency and flexibility of the emulsification property with homogeneous pressure were consistent with the homogeneous pressure. Correlation analysis suggested that the soy protein isolate flexibility had a linear positive correlation with the emulsifying activity and the emulsifying stability, and the correlation coefficients were 0.893 and 0.938, respectively. Through ultraviolet spectral scanning analysis of soy protein isolate and endogenous tryptophan fluorescence spectroscopy analysis, it was found that as the conformational flexibility of soy protein isolate was increased, the structure became more stretch.