大豆分离蛋白的磷酸化改性及功能性质的研究

采用三聚磷酸钠 (STP)对大豆分离蛋白 (SPI)进行化学改性 ,运用三因素二次饱和试验设计 ,得出最优试验回归方程为 :Y =2 8 2 6+5 89X1+0 93X2 +0 83X3-0 1 5 7X12 -1 2 6X2 2 +2 2 6X32 +0 65X1X2 -0 1 5X1X3+0 3 8X2 X3。并得出 6%大豆分离蛋白磷酸化程度最大的工艺条件是 pH 8 0 ,STP浓度为 3 %,45℃下反应 4h。同时研究了改性前后不同程度下SPI的功能性的变化 ,结果表明 ,改性后的SPI的溶解性、乳化能力、持水能力以及粘度等均有很大的提高 ,而发泡性无明显改善。通过红外光谱检测证明 ,STP与SPI反应是赖氨酸残基所进行的磷酸酯化反应。

Study on Phosphorylated Modification of Soybean Protein Isolate and Its Functional Properties

Sodium Tripolyphosphate (STP) is used as chemical agent to modify soybean protein isolate (SPI). The optimum regression equation is: Y=28 26+5 89X 1+0 93X 2+0 83X 3 -0 157X 1 2 -1 26X 2 2 +2 26X 3 2+ 0 65X 1X 2 -0 15X 1X 3+ 0 38X 2X 3 When the optimum condition of the highest degree of phosphorylation is 6% SPI and 3% STP at 45℃ with pH 8 0 for 4hours. The changes of functional propertities of SPI are determined in different degree of phosphorylation modification. The results showed that the solubility, emulsifying capacity, water holding capacity and viscosity except foaming ability had been improved after phosphorylation.The infra red spectra determination proved that the reaction between STP and SPI was phosphoramadation of lysine residues.