Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, United States.
US Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Food Composition and Methods Development Laboratory, Beltsville, MD 20705, United States.
J Colloid Interface Sci. 2015 Jan 15;438:130-137. doi: 10.1016/j.jcis.2014.09.055. Epub 2014 Sep 30.
Allyl isothiocyanate (AITC), an organosulfur compound in cruciferous vegetables, is a natural antimicrobial and potential chemopreventive agent. However, the instability of AITC in aqueous systems restrains its applications. In this study, oil-in-water AITC nanoemulsion was prepared by the emulsion inversion point (EIP) method, aiming at improving the aqueous stability of AITC. The optimal hydrophilic-lipophilic balance (HLB(op)) value of surfactants containing Tween 80 and Span 80 was established at 11.0-13.0, yielding nanodroplets with diameters of 137-215 nm. The mechanism of droplet formation within the HLP(op) region was discussed in terms of the possible structure of adsorbed surfactant layers at the oil-water interface in multiple emulsion droplets. In a 6.5-month storage test, the droplet sizes and the count rates (intensity of scattered light) of nanoemulsions decreased only slightly by 4-13% (depending on surfactant-to-oil ratio), even in highly diluted status, indicating the desirable stability of the nanoemulsions. Moreover, the nanoemulsion demonstrated superior protection against AITC degradation (78% remaining after 60 d at 30 °C), compared with protein nanoparticles as well as non-encapsulated aqueous dispersion. This work shows for the first time that AITC can be formulated into nanoemulsions and thus obtains satisfactory aqueous solubility and chemical stability.
丙烯基异硫氰酸酯（AITC）是十字花科蔬菜中的一种有机硫化合物，具有天然的抗菌作用，也是一种有潜力的化学预防剂。然而，AITC 在水相体系中的不稳定性限制了其应用。本研究采用乳化剂反转点（EIP）法制备了油包水型 AITC 纳米乳液，旨在提高 AITC 的水相稳定性。通过研究确定了包含吐温 80 和司盘 80 的表面活性剂的最佳亲水亲油平衡（HLB(op)) 值为 11.0-13.0，得到了直径为 137-215nm 的纳米液滴。在 HLB(op)区域内液滴形成的机制是根据多乳状液滴中油水界面处吸附表面活性剂层的可能结构来讨论的。在 6.5 个月的储存测试中，纳米乳液的粒径和计数率（散射光强度）仅略有下降（取决于表面活性剂与油的比例），下降幅度为 4-13%（这取决于表面活性剂与油的比例），即使在高度稀释的状态下，也表明纳米乳液具有良好的稳定性。此外，与蛋白质纳米颗粒和未包封的水相分散体相比，纳米乳液对 AITC 降解具有更好的保护作用（在 30°C 下 60 天后仍有 78%的 AITC 残留）。本研究首次表明，AITC 可以制成纳米乳液，从而获得令人满意的水溶性和化学稳定性。
