本研究以天然牛血清白蛋白（BSA）为蛋白模型，针对其制备的蛋白基高内相乳液（HIPEs）稳定性差的问题，在对蛋白不改性的基础上，改变乳化方式即采用两步乳化法能产生显著的改善效果。先用高能均质方式（高速均质30000 r/min、超声、微射流）制备出油相（φ）为0.2，体积平均粒径（d4,3）在17.60~0.425 μm范围内的初始乳液，即微乳滴；再用低能均质方式（高速均质13500 r/min），以微乳滴为类Pickering稳定剂制备φ为0.8的HIPEs。通过改变蛋白浓度和制备初始乳液的均质能量，制备了不同特性的HIPEs，并对初始乳液的界面蛋白吸附率（AP%）、粒径进行了表征，同时对HIPEs室温存储20 d前后的外观、微观结构和流变特征进行了观测。最后对初始乳液进行了去除游离蛋白的对比实验和HIPEs的热稳定性测试。结果显示蛋白浓度在1 wt%最合适，但即使低至0.1 wt%依然可以制备出倒置不流动的HIPEs。当微乳滴的d4,3在2.16 μm及以下时可以有效提升HIPEs的稳定性。研究表明，正是由于微乳滴的存在显著改善了HIPEs的储藏稳定性和热稳定性。

In this study, taking native bovine serum albumin (BSA) as the protein model, two-step emulsification was used to improve the stability of protein-based high internal phase emulsions (HIPEs) without causing protein denaturation. Firstly, an initial emulsion (micro-droplets) with φ as 0.2 and d4,3 (volume-averaged diameter) in the range of 17.60~0.42 μm, was prepared by high-energy homogenization (high speed homogenization 30000 r/min, ultrasonication and microfluidization). Then, HIPEs (φ=0.8) were fabricated using micro-droplets as the Pickering stabilizer through low-energy homogenization (high speed homogenization at 13500 r/min). HIPEs with different properties were prepared by changing the protein concentrations and the homogenization energy for the preparation of initial emulsions. The interfacial protein adsorption rate (AP%), particle size of the initial emulsions were characterized, while their appearance, microstructure and rheological characteristics were examined before and after a 20 day storage at room temperature. Finally, a comparative experiment to remove free proteins and a thermal stability test of HIPEs were conducted. It was found that the most suitable protein concentration was 1 wt%, even at a concentration as low as 0.1 wt%, HIPEs remained stable and still after being turned upside down. The stability of HIPEs was effectively improved when the d4,3 of micro-droplets was not higher than 2.16 μm. The results showed that the presence of micro-droplets significantly improved the storage stability and thermal stability of HIPEs.

国家自然科学基金资助项目（21872057）