Candelilla-shellac: An Alternative Formulation for Coating Apples

Abstract

An experimental candelilla-shellac formulation for coating apples (Malus ×domestica Borkh.) was developed and compared with commercial shellac-based and carnauba-shellac-based coatings on `Gala' and `Delicious' apples by determining effects on quality attributes, respiration, and internal atmospheres. Fruit were stored at 5 °C for 7 days followed by storage at 21 °C for 14 days. Gloss of `Delicious' apples coated with candelilla-shellac formulations containing 7% to 34% shellac increased with increasing shellac concentrations. `Gala' and `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 gloss, firmness, internal CO2, O2 and ethanol levels, steady-state respiration rate, 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 flavor scores than did apples receiving other coating treatments. Gloss of all coated fruit decreased with time, although shellac-coated fruit lost less gloss over the 21-day storage period. Analysis of gloss, firmness, fruit respiration, ethanol, weight loss, and flavor demonstrate that the candelilla formulation containing 34% shellac is competitive with current commercial carnauba-based apple-coating products.