碎米蛋白乳糖接枝物的超声制备及性质研究

Properties of broken rice protein-lactose grafts prepared by ultrasonic method

研究超声制备碎米蛋白-乳糖接枝物反应条件对接枝度的影响,并优化接枝反应条件。结果表明,超声功率、超声时间和蛋白浓度对接枝度有显著影响。优化工艺条件为:超声功率300 W,超声时间30 min,蛋白浓度12 mg·m L-1,在此条件下,产物接枝度为42.89%。溶解性在p H3~10的范围内显著提高;荧光光谱和氨基酸分析表明,接枝物具有美拉德反应特征,赖氨酸和精氨酸含量减少。接枝物与相同超声处理条件下的原蛋白比较,乳化活性有所增加,乳化稳定性改善显著,表面疏水性降低。

The effect of grafting reaction conditions on grafting degree of broken rice protein-lactose grafts prepared by ultrasonic method was studied. The result showed that the grafting degree was primarily affected by ultrasonic power, ultrasonic time and protein concentration. The optimum conditions were as follows： ultrasonic power, 300 W; ultrasonic time, 30 min; protein concentration, 12 mg·mL-1. Under this condition, the grafting degree was 42.89%. The solubility of grafts was significantly improved at pH 3-10. The amino acid analysis and fuorescence spectrum showed that grafts possessed the characteristic of Maillard reaction, and the contents of Arg and Lys decreased. Compared with the broken rice protein under the same ultrasonic treatment, the emulsion ability increased, the emulsion stability significantly improved and the surface hydrophobicity reduced as well.