Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 4, 1996
Publication Date: N/A
Interpretive Summary: Fresh citrus and many other fruits are coated in order to make them attractive to the consumer. The fruit coatings commonly used for citrus fruit, which have shellac or wood resin as the principal ingredients, serve well for most purposes, but they do have some disadvantages such as poor protection against weight loss, flaking, and being a barrier to the oxygen needed for respiration. These problems show the need to develop alternative coatings, and an attractive alternate would be a coating made with candelilla wax - even though such coatings tend to have low gloss - because candelilla wax coatings do not flake, are especially effective in preventing weight loss and allow the fruit to respire. The present paper shows how the gloss and permeability of candelilla wax coatings is altered by addition of gelatin and hydroxypropyl methylcellulose. These data are useful in designing fruit coatings.
Technical Abstract: Candelilla wax coatings and films were made by the drying of microemulsions. Addition of gelatin to ammonia-based candelilla wax microemulsions improved gloss, increased water vapor permeability and decreased oxygen permeability. Free-standing films were formed with addition of 30% or more gelatin or hydroxypropyl methylcellulose. As coatings on grapefruit, candelilla wax with up to 25% gelatin was usable, but coatings with high gelatin content formed such a barrier to gas exchange that the fruit underwent anaerobic fermentation. Candelilla wax microemulsions made with morpholine and minimal oleic acid had good gloss without addition of protein.