VOLATILE COMPOUNDS EMITTED BY GALA APPLES FOLLOWING DYNAMIC ATMOSPHERE STORAGE

Fruit quality and volatile compounds produced by apple fruit (Malus x domestica Borkh. 'Gala') were characterized following regular atmosphe re (RA) or controlled atmosphere (CA) storage at 1 OC. Static CA condi tions were 1, 1.9, 2.8, or 3.7 kPa O-2 Fruit stored under dynamic CA c onditions were exposed to ambient air 1, 2, or 3 days per week for 8 h ours then returned to 1 kPa O-2, All CA treatments included 2 kPa CO2. Ethylene production was reduced following CA storage plus 1 day at 20 degrees C compared with apples stored in IA, Apples stored in static 1 kPa O-2 and the dynamic treatments had lower ethylene production com pared with apples stored in 1.9 to 3.7 kPa O-2 after 90 and 120 days. Ethylene production by apples from all CA treatments recovered during a 7-day poststorage ripening period at 20 degrees C. Ester production was reduced following CA at 1 kPa O-2 after 60 days compared with RA-s tored fruit. Production of butyl acetate by apples stored in 1 kPa O-2 static CA was 29%, 30%, and 7% of that produced by RA-stored fruit af ter 60, 90, and 120 days storage plus 7 days at 20 degrees C, Amounts of 2-methylbutyl acetate were not affected by CA storage, however, pro duction of other 2-methylbutyrate esters was reduced following 1 kPa O -2 storage. Ester production increased with O-2 concentration after 90 days in storage. The dynamic treatments resulted in greater ester emi ssion after 120 days storage plus 7 days at 20 degrees C compared with apples stored in static 1 kPa O-2. Production of 1-methoxy-(2-propeny l) benzene by apples subjected to dynamic treatments was also higher a fter 120 days storage plus 7 days at 20 degrees C compared with apples stored in RA or static CA. No differences in firmness, titratable aci dity or soluble solids content were observed between apples stored in 1 kPa O-2 and the dynamic treatments. Firmness and titratable acidity were maintained better by dynamic treatments compared with static atmo spheres containing >1 kPa O-2.