ETHANOL VAPOUR TREATMENT AGAINST APPLE SUPERCIAL SCALD: HOW TO START A RESEARCH PROGRAM

We evaluated the efficacy of ethanol vapour treatment to control scald of Granny Smith apples, because diphenylamine treatment is not permitted by certain importing countries. In the first year, in a simple preliminary experiment on bagged fruits, ethanol at 3 g/kg, reduced scald compared with controls. In the second year, we observed that ethanol is more efficient in preventing scald when applied within one week after harvest. We found synergistic effects due to treatment combination: ethanol (8 g/kg) and controlled atmosphere (CA) (2 kPa O₂, 1 kPa CO₂). Ethanol vapour alone was not sufficient to control scald over a 3-5 month storage period, but headspace volume was different to the first year. CA alone prevented scald over a 4-month period, but following termination of CA treatment, scald was induced in the subsequent month in cold storage alone. The combination of ethanol treatment 1 week after harvest and CA prevented this later scald induction. Possible improvements to the treatments were considered.