超声波辅助碱提类PSE鸡肉分离蛋白-EGCG复合体系的理化特性

Physicochemical properties of ultrasound-assisted alkali extraction treated PSE-like chicken breast meat protein isolate-EGCG composite system

为了提高类PSE(Pale, Soft and Exudative)鸡肉分离蛋白的加工利用,防止表没食子儿茶素没食子酸酯(EGCG)的氧化降解,分析了碱溶酸沉法和超声波(20 kHz, 450 W,10 min)辅助碱提法(UAE)对类PSE鸡肉分离蛋白结构的影响及其对EGCG的保护作用。结果表明:与碱溶酸沉处理相比,经UAE提取的类PSE鸡肉分离蛋白的平均粒径和浊度减小、Zeta电位绝对值增加,添加EGCG后,复合体系的平均粒径明显减小(P<0.05);经UAE提取的类PSE鸡肉分离蛋白的α-螺旋与β-折叠相对含量分别下降至12.84%和11.96%,β-转角相对含量上升至63.17%(P<0.05),添加EGCG后α-螺旋相对含量下降至9.07%,β-折叠相对含量上升至19.08%(P<0.05);经UAE提取的类PSE鸡肉分离蛋白与EGCG之间具有更强的结合能力,结合位点较大(1.265),对EGCG的保护效果更好。UAE改变了类PSE鸡肉分离蛋白的结构,增强了类PSE鸡肉分离蛋白与EGCG的相互作用,减缓了EGCG被氧化降解。

In order to improve the utilization of PSE(Pale,Soft and Exudative)-like chicken breast meat protein isolate and to prevent the oxidative degradation of epigallocatechin-3-gallate(EGCG),the effects of alkali solubilization and extraction followed by acid deposition precipitation method and ultrasound(20 kHz,450 W,10 min)assisted alkali method extraction(UAE)on the structure of PSE-like chicken breast meat protein isolate and their protection on EGCG were analyzed.The results showed that the average particle size and turbidity of PSE-like chicken protein isolate obtained by UAE decreased and the absolute value of the potential increased compared to the alkali extraction followed by acid precipitation treatment,the average particle size of the composite system was significantly decreased after the addition of EGCG(P<0.05).The relative contents ofα-helix andβ-sheet of PSE-like chicken protein isolate by UAE-treated were decreased to 12.84%and 11.96%,respectively,while the relative content ofβ-turn was increased to 63.17%(P<0.05).The relative content ofα-helix decreased significantly to 9.07%and the relative content ofβ-sheet increased significantly to 19.08%after the addition of EGCG(P<0.05).The PSE-like chicken protein isolate obtained by UAE had the stronger binding ability to EGCG,with a larger binding site(1.265),and better protective effect on EGCG.UAE altered the structure of PSE-like chicken protein isolate,enhanced the interaction of PSE chicken protein isolate with EGCG,and slowed down the oxidative degradation of EGCG.