氧化单宁酸提高含猪血浆蛋白水解物的乳状液物理稳定性

Improvement of Physical Stability of Emulsion Containing Porcine Plasma Protein Hydrolysates by Oxidized Tannic Acid

在以猪血浆蛋白水解物(porcine plasma protein hydrolysates,PPPH)作为乳化剂所制备的水包油(oil-in-water,O/W)型乳状液中添加氧化单宁酸(oxidised tannic acid,OTA),研究OTA添加量对乳状液贮藏期间物理稳定性的改善,测定乳状液在贮藏期间的粒径、Zeta电位、絮凝指数、凝结指数和乳状液中蛋白质分配系数的变化趋势,并且利用激光共聚焦显微镜观察乳状液的微观结构。结果表明,在乳状液1~10 d的贮藏期间,与对照组相比,随着OTA添加量的增加,D[3,2]、D[4,3]、絮凝指数以及凝结指数显著降低(P<0.05),且在OTA添加量1%时达到最低(P<0.05);相反,Zeta电位随着OTA添加量的增加显著提高(P<0.05),且在OTA添加量1%时达到最高(P<0.05)。同时,OTA的添加在一定程度上促进了PPPH的交联,能够显著增加其在乳状液界面蛋白膜表面的分布(P<0.05);另外,乳状液的微观结构进一步验证OTA添加量1%的处理组能够在油滴表面形成最紧密和厚重的界面蛋白膜。研究结果表明,在PPPH制备的O/W型乳状液中添加OTA,能够显著提高其在整个储藏期间的物理稳定性,为OTA在乳状液食品中的应用提供了实验参考。

This study investigated the effect of adding oxidized tannic acid(OTA)to oil-in-water(O/W)emulsions prepared with porcine plasma protein hydrolysates(PPPH)as an emulsifier on improving their physical stability during storage.The changes in emulsion droplet size,Zeta potential,flocculation index,creaming index and protein partition coefficient during storage were determined,and the microstructure was visualized via confocal laser scanning microscopy(CLSM).The results showed that compared with the control group,D[3,2],D[4,3],flocculation index and coagulation index were decreased significantly with the increase in OTA concentration(P<0.05),whereas Zeta potential value was obviously increased(P<0.05),reaching its maximum when 1%OTA was added,during the period from 1 to 10 d of storage.Meanwhile,OTA slightly induced cross-linking of PPPH,significantly increasing their distribution at the emulsion interface(P<0.05).The CLSM micrographs also revealed that the interfacial membrane in emulsions with the addition of 1%OTA was more compact and more massive than other groups.The results indicated that the addition of OTA significantly improved the physical stability of O/W emulsions containing PPPH during storage,which will lay a theoretical foundation for the application of OTA in food emulsions.