Evaluation of a polyethylene-candelilla coating for 'Valencia' oranges

An experimental polyethylene-candelilla-wax coating formulation was evaluated in comparison to a high-gloss, shellac and wood resin citrus coating for storage of 'Valencia' oranges at 15-25 degrees C. Oranges with the wax coating had relatively high flavor scores (8.9-10.4) even after 9-16 days storage at 15-25 degrees C. By contrast, the high-gloss coating, shown to be typical of such citrus coatings, resulted in flavor scores as low as 3.7-4.1 after 9-16 days at 25 degrees C or 16 days at 21 degrees C. Flavor was especially low for fruit with internal O-2 < 1%. Flavor tended to decrease almost linearly with increasing ethanol content, which in turn was highly dependent on internal CO2. Oranges with the shellac and wood resin coating temporarily had better gloss than fruit with the wax coatings, but this advantage may lost after 8 days storage at 15-25 degrees C. Published by Elsevier Science B.V.