EFFECT OF COATINGS AND PROLONGED STORAGE-CONDITIONS ON FRESH ORANGE FLAVOR VOLATILES, DEGREES BRIX, AND ASCORBIC-ACID LEVELS

Valencia oranges were treated with a commercial polysaccharide-based c oating or a commercial shellac-based water wax or were left uncoated. The fruit were then stored at 16 or 21 degrees C with 95% relative hum idity for up to 56 days. Samples were periodically analyzed for intern al gases, flavor volatiles, water loss, degrees Brix, and ascorbic aci d. Coated fruit had lower internal O-2 and higher CO2 and ethylene con centrations than uncoated. Shellac-coated fruit had the lowest and hig hest amounts of O-2 and CO2, respectively, at 21 degrees C. Generally, coated fruit showed higher concentrations of many volatile compounds as time in storage increased, most notably ethanol, ethyl butanoate, e thyl acetate, and alpha-pinene. This was especially true for shellac-c oated fruit, for coated fruit at the higher storage temperature, and a fter the second month of storage. In contrast, levels of valencene, al pha-terpineol, and hexanol were generally lower in shellac-coated frui t and all coated fruit at the higher storage temperature. Several hydr ocarbon and minor alcohol volatiles increased then decreased during th e storage period. Some exceptions were alpha-pinene, sabinene, and iso butanol which generally increased in coated fruit by the end of the st orage period. Shellac-coated fruit had significantly less weight loss than fruit subjected to all other treatments, whereas polysaccharide-t reated fruit did not retard water loss compared to uncoated fruit. No significant differences were found for degrees Brix or ascorbic acid c oncentrations.