ARS | Publication request: Effect of Several Shiny Coatings on the Internal Gases and Quality of Applefruit

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: December 8, 2000
Publication Date: May 30, 2001

Technical Abstract: Zein, starch, polyvinyl acetate (PVA), carnauba, and carnauba-polysaccharide (CPS) coatings were applied post controlled atmosphere storage to Red Delicious apples for comparison to a commercial shellac coating. Coated apples were stored in air at 2C for two weeks and then removed to 21C for an additional two week simulated marketing period. Gloss, internal gases, weight loss, flesh firmness, sugars and acid content were measured. Gloss decreased during storage to similar levels for all coatings after the 4 week experimental period, although all of the coated fruits remained significantly glossier than uncoated controls. For uncoated apples, the difference in internal O2 and CO2 concentrations at ambient atmosphere was 1 to 2 percent at 2C, and increased one more percent after transfer to 21C. Fruits coated with shellac and starch showed higher than 10 percent internal CO2, and lower than 10 percent O2 at 21C. Zein-, PVA- and carnauba-coated apples showed moderate internal gases (6-7%CO2, 11-15%O2). Coated fruits exhibited less weight loss than uncoated except for those treated with the CPS coating, although the carnauba coating was the most effective water barrier. Starch-, shellac-, and CPS-coated fruit were firmer than those from other coating treatments, and all coated fruits were firmer than uncoated controls. Titratable acidity was higher in the fruits coated with CPS, starch, and shellac than in uncoated controls.