Edible Coatings from Morpholine-Free Wax Microemulsions

Abstract

Edible wax coatings were made by the drying of wax microemulsions composed of water, fatty acid, ammonia, and various combinations of candelilla wax, beeswax, carnauba wax, polyethylene wax, and petroleum wax. All 19 coating formulations studied were effective moisture barriers, with the best being those containing candelilla wax, beeswax, and petroleum wax. Polyethylene and carnauba wax coatings had best gloss, but also were the most brittle. Emulsion clarity was improved by using some myristic or palmitic acid, rather than commercial grade oleic acid as the only source of fatty acid. Compared to wax coatings made with ammonia-based emulsions, those made with morpholine had higher permeability to oxygen and water vapor, possibly because the morpholine, being less volatile than ammonia, stayed longer in the coating.