Submitted to: Metabolomics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/21/2011
Publication Date: 10/21/2011
Citation: Lee, J., Rudell Jr, D.R., Davies, P.J., Watkins, C.B. 2011. Metabolic changes in 1-methylcyclopropene (1-MCP)-treated ‘Empire’ apple fruit during storage. Metabolomics. doi: 10.1007/s11306-011-0373-5. Interpretive Summary: Firm flesh browning of apples is an economically cullable defect of apple fruit, especially ‘Empire’ in New York state. The disorder is characterized by moderate to severe, patterned browning of the flesh tissue. Very little is known about chemical changes that coincide with the injury or may provoke the injury. We used untargeted metabolic profiling to link changes in apple flesh chemistry caused by conditions that both reduce and/or provoke this injury. We found diverse compounds were linked with conditions and or actual injury and that changes in the overall chemistry occurred prior to symptom development.
Technical Abstract: ‘Empire’ apple fruit are more susceptible to flesh browning at 3.3 oC if first treated with 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception. To better understand the metabolic changes associated with this browning, untargeted metabolic profiling with partial least squares analysis has been used to visualize changes in the metabolic profile during hypoxic controlled atmosphere (CA) storage, ethylene insensitivity, and disorder development. Overall, carbohydrates and organic acids were not appreciably affected by 1-MCP, the levels of amino acids and volatile metabolites were significantly influenced by 1-MCP treatment. Sorbitol and levels of some amino acids were elevated towards the end of storage in 1-MCP treated fruit. CA storage reduced the levels of many volatile components and 1-MCP reduced these levels further. '-Aminobutyric acid (GABA) was associated with the development of flesh browning symptoms. Unlike other volatile compounds, methanol levels gradually increased with storage duration, regardless of 1-MCP treatment, while 1-MCP decreased ethanol production. Results reveal metabolic changes during storage that may possibly associated with development of flesh browning symptoms.