Stabilization of natural dye by encapsulation with inorganic host material for the application to safer colorant

天然存在的染料通常安全性上级，但稳定性较差。花青素是一种典型的天然染料，通过与介孔二氧化硅和层状化合物等无机主体材料复合，可以提高花青素的稳定性。当无机主体用表面活性剂适当改性以变得疏水时，亲脂性天然染料如β-胡萝卜素可以通过络合作用有效地掺入并稳定。在某些情况下，通过简单地混合染料和主体材料的粉末，能够制备天然染料和无机主体之间的复合材料。

Naturally occurring dyes are generally superior in safety but inferior in stability. The stability of anthocyanin, one of typical natural dyes, was able to be enhanced by making composites with several inorganic host materials, such as mesoporous silicas and layered compounds. When the inorganic host was properly modified with surfactants to become hydrophobic, the lipophilic natural dye such as beta-carotene can be effectively incorporated and stabilized by the complexation. The composite materials between the natural dye and the inorganic hosts were able to be prepared in some cases by simply mixing the powders of the dye and the host materials.