ARS | Publication request: CANDELILLA-SHELLAC - AN ALTERNATIVE FORMULATION FOR COATING APPLES (MALUS DOMESTICA BORKH)

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 2, 1999
Publication Date: N/A

Interpretive Summary: Apples are coated to improve their shine because consumers prefer to buy shiny apples. Shellac and carnauba wax, the materials currently in use, also have non-food uses. The apple industry is interested in finding substitutes for these materials in the event that labeling becomes mandatory and consumers become uncomfortable about the use of these materials on apples. In this work, candelilla, a natural plant wax, was evaluated as a substitute for carnauba wax and candelilla performed equally well.

Technical Abstract: An experimental candelilla-shellac formulation for coating apples was developed and compared with commercial shellac-based and carnauba- shellac-based coatings on 'Gala' and 'Red Delicious' apples to determine effects on quality attributes, respiration and internal atmospheres. Fruit were stored at 5 degrees C for 7 days followed by storage at 21 degrees C for 14 days. Gloss of 'Red Delicious' apples coated with candelilla-shellac formulations containing 7 to 34% shellac increased with increasing shellac concentrations. 'Gala' and 'Red Delicious' apples coated with a candelilla formulation containing 34% shellac maintained quality similar to those coated with commercial carnauba- shellac based coatings, as indicated by similarities in gloss, firmness, internal CO2 and O2, steady state respiration rate, ethanol, weight loss, and flavor. By comparison, shellac-coated fruit maintained the highest gloss throughout the experimental period. Shellac-coated apples were also firmer, contained more ethanol, and received higher sensory scores than apples receiving other coating treatments. Gloss of all coated fruit decreased with time, though shellac-coated fruit lost less gloss over the 21-day storage period.