Pirozzi Annachiara, Capuano Roberta, Avolio Roberto, Gentile Gennaro, Ferrari Giovanna, Donsì Francesco
Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
Institute for Polymers Composites and Biomaterials, National Research Council of Italy, Via Campi Flegrei 34, 80078 Pozzuoli, NA, Italy.
Foods. 2021 Aug 15;10(8):1886. doi: 10.3390/foods10081886.
This work aimed at studying the stabilization of O/W Pickering emulsions using nanosized cellulosic material, produced from raw cellulose or tomato pomace through different mechanical treatments, such as ball milling (BM) and high-pressure homogenization (HPH). The cellulose nanofibrils obtained via HPH, which exhibited longer fibers with higher flexibility than those obtained via ball milling, are characterized by lower interfacial tension values and higher viscosity, as well as better emulsion stabilization capability. Emulsion stability tests, carried out at 4 °C for 28 d or under centrifugation at different pH values (2.0, 7.0, and 12.0), revealed that HPH-treated cellulose limited the occurrence of coalescence phenomena and significantly slowed down gravitational separation in comparison with BM-treated cellulose. HPH-treated cellulose was responsible for the formation of a 3D network structure in the continuous phase, entrapping the oil droplets also due to the affinity with the cellulose nanofibrils, whereas BM-treated cellulose produced fibers with a more compact structure, which did adequately cover the oil droplets. HPH-treated tomato pomace gave similar results in terms of particle morphology and interfacial tension, and slightly lower emulsion stabilization capability than HPH-treated cellulose, suggesting that the used mechanical disruption process does not require cellulose isolation for its efficient defibrillation.
本研究旨在利用纳米级纤维素材料研究水包油（O/W）型皮克林乳液的稳定性，该材料由天然纤维素或番茄渣通过不同的机械处理制备而成，如球磨（BM）和高压均质（HPH）。通过HPH获得的纤维素纳米纤维比通过球磨获得的纤维素纳米纤维具有更长的纤维和更高的柔韧性，其特征在于较低的界面张力值和较高的粘度，以及更好的乳液稳定能力。在4℃下进行28天或在不同pH值（2.0、7.0和12.0）下离心进行的乳液稳定性测试表明，与BM处理的纤维素相比，HPH处理的纤维素限制了聚并现象的发生，并显著减缓了重力分离。HPH处理的纤维素导致在连续相中形成三维网络结构，由于与纤维素纳米纤维的亲和力也截留了油滴，而BM处理的纤维素产生具有更紧密结构的纤维，其不能充分覆盖油滴。HPH处理的番茄渣在颗粒形态和界面张力方面给出了类似的结果，并且乳液稳定能力略低于HPH处理的纤维素，这表明所使用的机械破碎过程不需要分离纤维素就能有效地进行纤维脱除。
