Fruit Metabolic Responses to Controlled Atmosphere Oxygen and/or Carbon Dioxide Stress
2012 Annual Report
1a.Objectives (from AD-416):
1. Identify volatile compounds that accumulate during CA storage.
2. Characterize volatile compound dynamics during storage in atmospheres that induce low O2 and/or high CO2 injury.
3. Determine if recognition of changes in volatile compound production during low O2 or high CO2 stress has utility for CA system management.
4. Develop sampling protocols to enable detection of biomarkers for scald and other disorders.
1b.Approach (from AD-416):
An untargeted analysis of volatile compounds in controlled atmosphere chambers and rooms will be conducted using current analytical technologies. Impacts on volatile production from pre-storage treatments (DPA, SmartFresh), as well as timing and duration of O2 and/or CO2 stress will be evaluated. Analyses will primarily be conducted using gas chromatography/mass spectrometry which provides highly informative qualitative and quantitative results with high sensitivity.
This project relates to objective 1 of the associated in-house project which seeks to identify factors that influence postharvest fruit quality and development of market limiting physiological disorders. The project’s objective is to characterize volatile compounds produced by apple fruit during storage in controlled atmospheres known to induce physiological disorders. During 2012, ARS scientists at the Tree Fruit Research Laboratory in Wenatchee, Washington, confirmed identification of volatile compounds for which ethanol is required. They observed the production in much larger amounts by Delicious apples during storage in 0.3% oxygen compared to fruit stored in 0.8 or 1.6% oxygen. However, differences in ethanol accumulation were not observed during the first several months in storage. Volatile compounds for which butyric acid is required for production are produced in larger amounts by Fuji apples stored in 5% carbon dioxide (with 1% oxygen), and butyric acid accumulation increased with carbon dioxide concentration. The results indicate non-invasive assessment of apple fruit volatile accumulation may provide a means to monitor fruit condition during controlled atmosphere storage.