Solvent-free fabrication of slippery coatings from edible raw materials for reducing yogurt adhesion

In this article, a novel slippery coating was fabricated from edible beeswax and sunflower oil via two steps. Firstly, an oleogel layer was formed on polyolefin substrate via cooling the hot beeswax and sunflower oil solution at ambient condition. Owing to the adsorption of the oleogel, sunflower oil was then sprayed and immobilized on oleogel layer to form the slippery coating with dual-layer structure. This solvent-free fabrication process was facile and green, and used only sustainable raw materials. The performances such as gel-to-sol dissociation temperature (defined as Tgel) and the adsorption for sunflower oil of the oleogel layers were modulated by the contents of beeswax. Sliding experiments on the slippery coating were carried out by using yogurt as the testing liquid. Owing to the liquid-liquid sliding, this coating displayed good sliding effect, thus greatly reducing yogurt adhesion on its surface. After thirty days storage in a refrigerator, this coating still exhibited the desired sliding effect for yogurt, revealing its application potential in reducing liquid food residue and waste.