Curcumin (Cur) as a natural pigment and biological component, can be widely used in food and beverages. However, the water insolubility of Cur significantly limits its applications. In this study, we prepared a series of nanocrystals via ultrasound-assisted method to improve the solubility and availability of Cur. The results showed artemisia sphaerocephala krasch polysaccharide (ASKP), gum arabic (GA) and wheat protein (WP) were outstanding stabilizers for nanocryatals except traditional agent, poloxamer 188 (F68). The obtained curcumin nanocrystals (Cur-NC) displayed a rod-shaped, crystal- and nanosized structure, and extremely high loading capacity (more over 80 %, w/w). Compared with raw powder, Cur-NC greatly improved the water solubility and dispersibility, and the slow and complete release of Cur of Cur-NC also endowed them excellent antioxidant capacities even at 10 μg/mL. Importantly, as functional factor additive in beverages (e.g. water and emulsion), Cur-NC could increase the content of Cur to at least 600 μg/mL and retain a good stability. Overall, we provided an effective improvement method for the liposoluble active molecules (e.g. Cur) based on the nanocrystals, which not only tremendously enhanced its water solubility, but also strengthened its bioactivity. Notably, our findings broadened the application of water-insoluble compounds.

中文翻译：

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超声辅助法制备的具有极高溶解度和分散度的姜黄素纳米晶的构建、表征及生物活性评价

姜黄素（Cur）作为一种天然色素和生物成分，可广泛应用于食品和饮料中。然而，Cur的水不溶性极大地限制了其应用。在本研究中，我们通过超声辅助方法制备了一系列纳米晶体，以提高 Cur 的溶解度和利用率。结果表明，除了传统剂泊洛沙姆188（F68）外，白蒿多糖（ASKP）、阿拉伯树胶（GA）和小麦蛋白（WP）都是纳米晶的优异稳定剂。所获得的姜黄素纳米晶体（Cur-NC）呈现出棒状、晶体和纳米尺寸的结构，以及极高的负载量（超过80%，w/w）。与原粉相比，Cur-NC大大提高了水溶性和分散性，而且Cur-NC缓慢而完全的Cur释放也使其即使在10 μg/mL的浓度下也具有优异的抗氧化能力。重要的是，作为饮料（如水和乳液）中的功能因子添加剂，Cur-NC可以将Cur含量提高到至少600 μg/mL，并保持良好的稳定性。总的来说，我们为基于纳米晶的脂溶性活性分子（例如Cur）提供了一种有效的改进方法，不仅极大地提高了其水溶性，而且增强了其生物活性。值得注意的是，我们的研究结果拓宽了水不溶性化合物的应用。