The presence of emulsifiers facilitates the formation of nanoemulsions and assists in their stabilisation. Moreover, behaviour of nanoemulsions along the gastrointestinal tract primarily depends on their composition, affecting the bioaccessibility of the encapsulated compound. The goal of this work was to study how β-carotene-enriched nanoemulsions prepared with different emulsifiers (Tween 20, lecithin, sodium caseinate, sucrose palmitate) at various concentrations (2%–8%) would affect their stability (particle size and zeta potential) during an in vitro gastrointestinal tract (GIT) digestion. In addition, the lipid digestibility and β-carotene's bioaccessibility of nanoemulsions was determined. Nanoemulsions stabilised with Tween 20, lecithin and sodium caseinate did not present any variation in particle size under stomach phase. After the intestinal GIT phase, all nanoemulsions experienced physical changes, i.e. either increase or decrease in their particle size depending on the nature and concentration of the emulsifier used. The zeta potential of all nanoemulsions was maintained negative throughout the GIT digestion; moreover, it was less negative after the stomach GIT phase (between −24.2 and −1.4 mV). Lecithin-stabilised nanoemulsions presented the highest number of free fatty acids when the emulsifier concentration increased from 2% to 8%. In this sense, nanoemulsions containing 8% of lecithin exhibited the highest β-carotene bioaccessibility (23.5%), suggesting that lecithin can enhance lipid digestion and bioaccessibility of β-carotene encapsulated within nanoemulsions. This study elucidates the importance of not only the emulsifier's nature but also the concentration used when designing nanoemulsions as delivery systems for lipophilic compounds.

中文翻译：

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乳化剂的性质和浓度对体外消化 过程中富含β-胡萝卜素的纳米乳稳定性的影响

乳化剂的存在促进了纳米乳液的形成并有助于其稳定化。而且，纳米乳剂沿着胃肠道的行为主要取决于它们的组成，影响包封化合物的生物可及性。这项工作的目的是研究用不同浓度（2％–8％）的不同乳化剂（吐温20，卵磷脂，酪蛋白酸钠，蔗糖棕榈酸酯）制备的富含β-胡萝卜素的纳米乳剂如何影响其稳定性（粒径和Zeta）电势）期间在体外胃肠道（GIT）消化。此外，测定了纳米乳剂的脂质消化率和β-胡萝卜素的生物利用度。用吐温20，卵磷脂和酪蛋白酸钠稳定的纳米乳剂在胃相下粒径没有变化。在肠道GIT阶段之后，所有纳米乳剂都经历了物理变化，即取决于所用乳化剂的性质和浓度，它们的粒径可以增加还是减小。在整个GIT消化过程中，所有纳米乳剂的Zeta电位均保持为负。此外，在胃GIT阶段后（-24.2至-1.4 mV之间），它的阴性率更低。当乳化剂的浓度从2％增加到8％时，卵磷脂稳定的纳米乳液呈现出最多的游离脂肪酸数量。从这个意义上讲，含有8％卵磷脂的纳米乳剂具有最高的β-胡萝卜素生物可及性（23.5％），这表明卵磷脂可以增强脂质消化和包裹在纳米乳剂中的β-胡萝卜素的生物可及性。这项研究阐明了不仅乳化剂的重要性，