油菜蜂花粉蛋白水解度测定方法比较

采用Alcalase 2.4L FG 水解油菜蜂花粉蛋白，比较pH stat 法、OPA 法和TNBS 法测定蜂花粉蛋白水解度的差异。水解118min 后，pH stat 法、OPA 法和TNBS 法测得的水解度分别为24.7% ﹑ 13.4% ﹑ 6.6%。由于OPA试剂和甘氨酸﹑半胱氨酸﹑赖氨酸反应生成的化合物在340nm 波长处的吸光度较低，致使OPA 法测得的水解度低。TNBS 试剂和ε-NH2 的作用不稳定，也可能是由于TNBS 试剂产生的发光物使测定结果降低。在水解度较低的情况下，α-NH2 平均解离度的变化可以忽略，pH stat 法测得的水解度比较准确。

Comparison of Methods for Determining the Hydrolysis Degree of Rape Bee Pollen Protein

Rape bee pollen protein was hydrolyzed with Alcalase 2.4L, and the change in degree of hydrolysis (DH) during hydrolysis was determined by pH stat method, OPA method or TNBS method, and differences in determination results were analyzed. DH derived from 118 min hydrolysis was measured by pH stat, OPA and TNBS methods to be 4.7%, 13.4% and 6.6%, respectively. Due to lower absorbance at 340 nm of the products of reaction among OPA reagent, lycine, cysteine and lysine, the determination by OPA method gave a lower DH. Unstable reaction between TNBS reagent and ε-NH2 was likely to due to the presence of certain luminescent substances generated from TNBS reagent. In the case of lower DH, the change in average degree of dissociation of α-NH2 groups could be neglected. In conclusion, pH stat method is a more accurate method than the two other ones.