氧化咖啡酸交联乳清蛋白膜的物理性能

咖啡酸氧化后与乳清蛋白交联成膜，对膜的机械性能、吸水性能、浸出率及其浸出物分子质量进行测试。结果显示：氧化后的咖啡酸能够作为交联剂提高乳清蛋白膜拉伸强度、杨氏模量及膜材料的吸水率，但对膜的断裂伸长率没有显著影响。蛋白膜在pH 3～5的Mc Ilvaine缓冲液浸出率略微降低，而在pH 6和pH 7条件下则显著提高；SDS-PAGE实验表明，在pH 6时，浸出物主要是由二硫键支配的聚合物。

Physical Properties of Oxidized Caffeic Acid Cross-Linked Whey Protein Films

Oxidized caffeic acid (OCA) was used to cross-link whey proteins for making cast films. The prepared films were analyzed for mechanical properties, water binding capacity, and protein solubility in Mc,Ilvaine buffer (pH 3 to 7) and the molecular weight of leached fractions. The results showed that the tensile strength, Young’s modulus and water binding capacity of films was markedly increased but its extensibility was not affected by the OCA incorporation. The degree of swelling significantly increased with increasing OCA concentrations. The protein solubility (leachability) of OCA-treated films slightly decreased at pH 3－5 but noticeably increased at pH 6 and 7 compared to untreated (control) films. Electrophoresis indicated that disulfide-linked proteins were the dominant components in leached fractions in pH 6 buffer solution.