β-Carotene has been widely investigated both in the industry and academia, due to its unique bioactive attributes as an antioxidant and pro-vitamin A. Many attempts were made to design delivery systems for β-carotene to improve its dispersant state and chemical stability, and finally to enhance the functionality. Different types of oil-in-water emulsions were proved to be effective delivery systems for lipophilic bioactive ingredients, and intensive studies were performed on β-carotene emulsions in the last decade. Emulsions are thermodynamically unstable, and emulsions with intact structures are preferable in delivering β-carotene during processing and storage. β-Carotene in emulsions with smaller particle size has poor stability, and protein-type emulsifiers and additional antioxidants are effective in protecting β-carotene from degradation. Recent development in the design of protein-polyphenol conjugates has provided a novel approach to improve the stability of β-carotene emulsions. When β-carotene is consumed, its bioaccessibility is highly influenced by the digestion of lipids, and β-carotene in smaller oil droplets containing long-chain fatty acids has a higher bioaccessibility. In order to better deliver β-carotene in complex food products, some novel emulsions with tailor-made structures have been developed, e.g., multilayer emulsions, solid lipid particles, Pickering emulsions. This review summarizes the updated understanding of emulsion-based delivery systems for β-carotene, and how emulsions can be better designed to fulfill the benefits of β-carotene in functional foods.

中文翻译：

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在复杂食品系统中输送β-胡萝卜素的乳液设计

由于β-胡萝卜素具有独特的生物活性属性，​​即抗氧化剂和维生素A，因此在业界和学术界都得到了广泛的研究。人们为设计β-胡萝卜素的输送系统进行了许多尝试，以改善其分散状态和化学稳定性，最后增强功能。事实证明，不同类型的水包油乳剂是亲脂性生物活性成分的有效递送系统，并且在过去十年中对β-胡萝卜素乳剂进行了深入研究。乳液是热力学不稳定的，并且具有完整结构的乳液优选在加工和储存过程中递送β-胡萝卜素。粒径较小的乳液中的β-胡萝卜素稳定性较差，蛋白质型乳化剂和其他抗氧化剂可有效防止β-胡萝卜素降解。蛋白质-多酚共轭物设计的最新进展提供了一种改善β-胡萝卜素乳剂稳定性的新颖方法。当β-胡萝卜素被消耗时，其生物可及性受到脂质消化的高度影响，并且在含有长链脂肪酸的较小油滴中的β-胡萝卜素具有较高的生物可及性。为了更好地在复杂食品中输送β-胡萝卜素，已开发出一些具有量身定制结构的新型乳剂，例如多层乳剂，固体脂质颗粒，Pickering乳剂。这篇综述总结了对基于乳化剂的β-胡萝卜素递送系统的最新了解，以及如何更好地设计乳剂以实现功能性食品中的β-胡萝卜素的益处。