Abstract：
The oil extracted from baru (Dipteryx alata Vog.) seeds is in bioactive compounds and it presents potential to be used in food and cosmetic industries. Therefore, this study aims to provide insights into the stability of baru oil-in-water (O/W) nanoemulsions. For this purpose, the effects of the ionic strength (0, 100 and 200 mM), pH (6, 7 and 8), and storage time (28 days) on the kinetic stability of these colloidal dispersions were evaluated. The nanoemulsions were characterized in terms of interfacial properties, rheology, zeta potential (ζ), average droplet diameter, polydispersity index (PDI), microstructure, and creaming index. In general, for samples, the equilibrium interfacial tension ranged from 1.21 to 3.4 mN.m-1, and the interfacial layer presented an elastic behavior with low dilatational viscoelasticity. Results show that the nanoemulsions present a Newtonian flow behavior, with a viscosity ranging from 1.99 to 2.39 mPa.s. The nanoemulsions presented an average diameter of 237-315 nm with a low polydispersity index (<0.39), and a ζ-potential ranging from 39.4 to 50.3 mV after 28 days of storage at 25 °C. The results obtained for the ζ-potential suggest strong electrostatic repulsions between the droplets, which is an indicative of relative kinetic stability. In fact, macroscopically, all the nanoemulsions were relatively stable after 28 days of storage, except the nanoemulsions added with NaCl. Nanoemulsions produced with baru oil present a great potential to be used in the food, cosmetic, and pharmaceutical industries.
摘要：
从baru（DipteryxalataVog。）种子是生物活性化合物，它具有用于食品和化妆品行业的潜力。因此,这项研究旨在提供见解的稳定性baru水包油（O/W）纳米乳液。为此,离子强度(0、100和200mM)的影响，pH（6、7和8），和储存时间(28天)对这些胶体分散体的动力学稳定性进行了评价。纳米乳液在界面性质方面进行了表征，流变学,ζ电位(ζ)，平均液滴直径,多分散指数(PDI)，微观结构，和乳化指数。总的来说,对于样品，平衡界面张力范围为1.21至3.4mN。m-1，界面层表现出具有低膨胀粘弹性的弹性行为。结果表明，纳米乳液呈现牛顿流动行为，粘度范围为1.99至2.39mPa.s。纳米乳液的平均直径为237-315nm，具有低多分散指数（<0.39），在25°C下储存28天后，ζ电位为39.4至50.3mV。ζ电位获得的结果表明，液滴之间存在强烈的静电排斥，这是相对动力学稳定性的指示。事实上,宏观上,所有纳米乳液在储存28天后相对稳定，除了添加有NaCl的纳米乳液。用baru油生产的纳米乳液在食品中具有巨大的应用潜力，化妆品,和制药行业。
