Production of volatile compounds by fuji apples following exposure to high CO2 or low O2

The emission of volatile compounds by Fuji apples following short- or long-term exposure to high CO2 was studied. The production of ethanol, methyl and ethyl esters, octanal, nonanal, and decanal was enhanced while the production of C-3-C-6 alcohols, propyl, butyl, pentyl, and hexyl esters and butanal decreased in fruit exposed to 10 kPa O-2 + 20 kPa CO2 at 20 degreesC for up to 12 days. The impact of high CO2 exposure on volatile production was dependent on fruit maturity at harvest. Apples stored for 8 months in an ultralow O-2-controlled atmosphere (CA) (0.5 kPa O-2 + 0.05 kPa CO2) or high CO2 CA (1.5 kPa O-2 + 3 kPa CO2) at 0.5 degreesC had reduced production of most volatiles, especially butyl and hexyl esters, as compared to fruit stored in air. Two exceptions were ethanol and ethyl acetate for which the production was enhanced by both CA regimes. Treatment with the antioxidant diphenylamine prior to storage prevented most of the high CO2-induced and ultralow O-2-induced changes in volatile production. The results of this study do not indicate that changes in volatile production following the exposure of Fuji apples to high CO2 are causally related to the development of CO2 injury.