State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering , China University of Petroleum (East China) , Qingdao 266580 , P.R. China.
J Agric Food Chem. 2019 Sep 11;67(36):10155-10164. doi: 10.1021/acs.jafc.9b02379. Epub 2019 Sep 3.
Stabilization of Pickering emulsions via particles of biological origin exhibits a great potential to be widely applied in food, cosmetic, or biomedicine formulation because of their excellent biocompatibility, biodegradability, and functional properties. This paper describes the successful development of a bioderived GroEL protein nanobarrel as a Pickering stabilizer and its protective properties on β-carotene in dispersed oil phase, as a model of labile bioactive compounds. It is shown that the GroEL nanobarrel is highly surface-active and allows the formation of Pickering emulsion by physical adsorption at the oil/water interface. The optimized formulation for generating a stable submicron oil droplet by ultrasonication includes a GroEL concentration of 0.05-0.45 wt % with an oil/water volume ratio of 0.05-0.35. The as-prepared Pickering emulsion shows pH-responsive emulsification/demulsification transition and excellent stability at temperatures less than 65 °C and ionic strength (with NaCl addition) up to 500 mM. Meanwhile, the emulsion tends to form a gel-like network structure with the oil/water ratio increasing. Finally, we demonstrate that possible factors of oxidant, reducing agent, UV radiation, and sucrose have sequentially decreasing to no effect on the stability of β-carotene encapsulated in GroEL-stabilized Pickering emulsion and that higher GroEL concentration can significantly reduce β-carotene degradation rate, thus ensuring more efficient long-term storage. We believe that the emulsion system supported by the GroEL nanobarrel could be developed to a viable tool for delivering lipophilic bioactive compounds.
基于生物来源的颗粒稳定的 Pickering 乳液由于其优异的生物相容性、生物可降解性和功能特性，在食品、化妆品或生物医学制剂中有广泛应用的潜力。本文描述了成功开发的生物衍生 GroEL 蛋白纳米桶作为 Pickering 稳定剂，及其对分散油相中的β-胡萝卜素（作为不稳定生物活性化合物的模型）的保护性能。结果表明，GroEL 纳米桶具有很高的表面活性，通过在油水界面的物理吸附允许形成 Pickering 乳液。通过超声处理生成稳定的亚微米油滴的最佳配方包括 GroEL 浓度为 0.05-0.45wt%，油/水体积比为 0.05-0.35。所制备的 Pickering 乳液表现出 pH 响应的乳化/破乳转变，在低于 65°C 和离子强度（添加 NaCl）高达 500mM 的温度下具有优异的稳定性。同时，随着油/水比的增加，乳液趋向于形成凝胶状网络结构。最后，我们证明了氧化剂、还原剂、UV 辐射和蔗糖等可能的因素对 GroEL 稳定的 Pickering 乳液中包封的β-胡萝卜素的稳定性依次递减，没有影响，并且较高的 GroEL 浓度可以显著降低β-胡萝卜素的降解速率，从而确保更有效的长期储存。我们相信，由 GroEL 纳米桶支撑的乳液系统可以开发成为递送脂溶性生物活性化合物的可行工具。
