Title: Apple fruit volatile compound dynamics during storage in low O2 or high CO2 atmospheres Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 23, 2013
Publication Date: June 4, 2013
Citation: Lumpkin, C., Rudell Jr, D.R., Fellman, J.K., Mattheis, J.P. 2013. Apple fruit volatile compound dynamics during storage in low O2 or high CO2 atmospheres. XI International Controlled and Modified Atmosphere Research Conference Book of Abstracts. p. 14. Technical Abstract: Long term controlled atmosphere (CA) storage of apples prolongs postharvest life and impacts fruit volatile compound production after fruit are removed from storage. As less is known regarding fruit volatile dynamics during storage, studies were conducted to characterize volatile compounds present during CA of two cultivars susceptible low O2 (‘Delicious’) or high CO2 (‘Fuji’) injury. All fruit was held at 0.5 oC. ‘Delicious’ apples were stored in air or 0.2–1.6 kPa O2 with 1 kPa CO2, and ‘Fuji’ apples in air or 0.5, 1.5, or 5.0 kPa CO2 with 1 kPa O2. Storage chamber headspace was pumped through traps containing Tenax onto which volatile compounds were collected, and samples were analyzed by GC-MS. CA storage conditions prolonged storage life, reduced ethylene production, disorder incidence, and losses in firmness, soluble solids, and titratable acidity. Volatile production differed quantitatively for each cultivar by O2 or CO2 concentration and storage duration. Impacts of atmospheres on chamber volatile content were greatest during the first 2 or 6 months storage for ‘Fuji’ and ‘Delicious’ respectively. CO2 injury incidence was present after 4 months storage and incidence was highest in fruit stored in 5.0 kPa CO2. All CA chambers had reduced accumulation of butyl, hexyl, and propyl esters but increased methyl and ethyl esters relative to fruit stored in air. Although ‘Fuji’ methyl ester accumulation increased with increased kPa CO2, storage treatment differences were relatively small. ‘Delicious’ apples stored in 0.3 kPa O2 developed stem browning and fruit removed after 1 or more months had off-odors. Acetaldehyde, ethyl esters, and ethanol levels increased with decreased kPa O2, and accumulation of volatiles typical of ripening ‘Delicious’ apples decreased. Dynamics of ethanol accumulation differed in the two study years, but ethanol accumulated in excess of 10 'mol L-1 only in chambers maintained at the lowest kPa O2.