氧化胁迫下桑椹多酚及其微胶囊对肌原纤维蛋白结构及凝胶性能的调控

Regulation of Mulberry Polyphenols and Their Microcapsules on the Structure and Gel Properties of Myofibrillar Proteins under Oxidative Stress

摘要:

该研究探究了LOX氧化体系下桑椹多酚（MP）及桑椹多酚-β-环糊精微胶囊（MPM）对猪肉肌原纤维蛋白结构与功能特性的影响。分别向肌原纤维蛋白中添加桑椹多酚、β-环糊精（β-CD）和桑椹多酚-β-环糊精微胶囊，经LOX氧化体系氧化后，分析桑椹多酚及其微胶囊对肌原纤维蛋白的结构和凝胶性能的影响。桑椹多酚可以有效抑制氧化过程中肌原纤维蛋白的羰基化、减少巯基向二硫键的转化，改善凝胶持水性。与氧化组相比，经过桑椹多酚处理后，羰基含量下降了33.33%，巯基含量提高了54.87%，二硫键含量下降了19.38%，使蛋白质的凝胶持水性从20.22%提高到了23.11%（p<0.05），但经桑椹多酚修饰后的肌原纤维蛋白热稳定性下降；β-CD对桑椹多酚进行包埋处理可减弱桑椹多酚对肌原纤维蛋白凝胶白度的负面影响，并通过强化蛋白质间的氢键作用进一步改善凝胶结构和持水性。以上研究表明，以β-环糊精为壁材制备桑椹多酚微胶囊有助于改善肌原纤维蛋白的氧化稳定性和凝胶结构，有望作为一种蛋白质氧化调节剂用于肉制品加工。

Abstract:

The effects of mulberry polyphenols (MPs) and mulberry polyphenols-β-cyclodextrin (CD) microcapsules (MPMs) on the structure and functional properties of pork myofibrillar proteins in a LOX oxidation system were investigated. MPs, β-CD and MPMs were respectively added to myofibrillar proteins, and oxidation in the LOX oxidation system. Then, the effects of MPs and their microcapsules on the structure and gel properties of myofibrillar proteins were analyzed. MPs could effectively inhibit the carbonylation of myofibrillar protein, reduce the conversion of sulfhydryl groups to disulfide bonds, and improve the water-holding capacity of protein gel. Compared with the oxidation group, after the treatment with MPs, the carbonyl content decreased by 33.33%, the sulphydryl content increased by 54.87%, and the disulfide bond content decreased by 19.38%, which increased the water-holding capacity of the proteins from 20.22% to 23.11% (p<0.05), but the thermal stability of myofibrillar proteins modified with MPs. The encapsulation of MPs by β-CD decreased the negative effect of MPs on the whiteness of gel, and improved the structure and water-holding capacity of the gel through strengthening the hydrogen bonds between proteins. These above results showed that the MPMs made with β-CD as the wall material helped improve the oxidative stability and gel structure of myofibrillar proteins, and are expected to be used as a protein oxidation regulator for meat processing.