纤维素纳米晶（CNCs）由于其表面固有的强亲水性，往往需要修饰改性才能应用，如乳液稳定。该文研究了三种蛋白（牛血清蛋白BSA、酪蛋白酸钠CAS和大豆分离蛋白SPI）通过静电修饰CNCs表面性质的可行性，并研究了其对CNCs乳液体外消化特性的影响。首先研究了pH值3.0时蛋白与CNCs的作用模式、吸附比例、颗粒结构特征，结果发现二者可以通过静电作用结合（Zeta电位由-35 mV至+20 mV），CNCs表面蛋白吸附比例由100%（蛋白浓度0~0.1%，m/V）逐渐降低至40%~60%（蛋白浓度0.5%，m/V）。静电修饰引起CNCs絮凝，显著改善其两亲性（接触角由35°增加至75°~80°）。然后研究了蛋白包覆CNCs的乳化性质，结果发现蛋白包覆CNCs形成了粒径为3~9 μm的絮凝乳液，且凝聚稳定性更好，不同蛋白之间无显著差异。体外消化结果表明，与吐温20乳液（~90%）相比，蛋白包覆CNCs稳定乳液具有更低的游离脂肪释放率（~80%），蛋白种类影响不显著。可见，三种常见蛋白能够通过静电吸附方式修饰CNCs并将其转化为良好的Pickering稳定剂。该文研究结果能够极大丰富食品级皮克林稳定剂的来源，并促进相关功能乳液食品的开发。

Cellulose nanocrystals (CNCs) are modified for emulsion stabilization purposes due to their intrinsic strong hydrophilicity. The purpose of this study was to investigate the feasibility of using three proteins (bovine serum protein/BSA, sodium caseinate/CAS, and soy protein isolate/SPI) for modifying the surface properties of CNCs through electrostatic modification and their impacts on the in vitro digestion properties of CNC emulsions. The three proteins and CNCs were first investigated for their interaction profiles, protein adsorption percentages, and particle structure characteristics at pH 3.0. The electrostatic interaction was found to be able to combine them (zeta potential between -35 and +20 mV). Meanwhile, the adsorption of proteins on CNC surfaces was gradually reduced from 100% (protein concentration at 0~0.1% m/V) to 40%~60% (protein concentration at 0.5% m/V). Electrostatic modification caused CNCs to flocculate and become significantly more amphiphilic (contact angle increased from 35° to 75°~80°). It was found that protein-coated CNCs formed flocculated emulsions with particle sizes of 3~9 μm and had better coalescence stability, with no significant differences between the three proteins. The simulated in vitro digestion results show that protein-coated CNC-stabilized emulsions released less free fatty acid (~80%) than the Tween 20 emulsion (90%), with no significant difference between different protein coatings. It can be seen that the common three proteins can be used to modify CNCs by electrostatic adsorption and transform them into good Pickering stabilizers. The findings in this paper can greatly enrich the source of food-grade Pickering stabilizers and promote the development of related functional emulsions for the food industry.

广东省基础与应用基础研究基金（2021A1515010637）