Edible Coatings from Candelilla Wax Microemulsions
Candelilla wax is obtained from the desert plant Euphorbia antisyphilitica. The possibility of developing improved candelilla wax coating formulations with good gloss and satisfactory gas barrier properties for use as fruit coatings and also as edible coatings for other food applications was investigated. Gelatin and hydroxypropylmethylcellulose (HPMC) were selected as additives as they are generally good film-formers and are known to be compatible with wax microemulsions. >70 candelilla wax microemulsions of different formulations were made, which were either ammonia-based or morpholine-based. The emulsifier used was either oleic or palmitic acid. The gloss of coatings made from ammonia-based microemulsions was improved by addition of gelatin or HPMC, which also decreased O2 permeability and decreased water vapour permeability. Candelilla wax containing <=25% gelatin was usable as a coating for grapefruit ; higher gelatin contents resulted in anaerobic fermentation. Candelilla coatings with good gloss were also made from morpholine-based wax microemulsions with minimal oleic acid content.