Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 3/31/2005
Publication Date: 7/1/2005
Citation: Mattheis, J.P., Rudell Jr, D.R. 2005. Metabolism of apple peel constituents during ripening is differentially regulated by ethylene. Meeting Abstract.
Technical Abstract: Metabolism of pigments and other peel constituents was assessed during ripening of 'Delicious' and 'Golden Delicious' apples. The ethylene action inhibitor 1-methylcyclopropene (1-MCP) and/or low oxygen controlled atmosphere storage (CA) were used to limit ethylene activity during and after storage at 1 deg C. 'Delicious' apples not exposed to 1-MCP developed a brownish discoloration (not superficial scald) during the initial 2 months storage. LC/MS analyses of peel components indicated 1-MCP and/or CA inhibited the degradation of compounds responsible for red peel color (i.e. idaein) as well as other flavonoids. Ethylene regulation of metabolism of other phenolic and related constituents including (-)epicatechin and chlorogenic acid appears to be compound specific. (-)Epicatechin content is not impacted by 1-MCP or CA, while chlorogenic acid accumulation is reduced in fruit exposed to 1-MCP and/or stored in CA. Both of these compounds are brown when oxidized. ß-carotene and lutein content in peel of 'Delicious' fruit stored in air was lower compared to untreated controls. Chlorophyll degradation was enhanced in air-stored fruit previously exposed to 1-MCP, however, this result was not observed in 1-MCP exposed fruit from CA. Results for 'Golden Delicious' apples also indicated exposure to 1-MCP, CA, as well as storage duration impact metabolism of peel constituents. Chlorophyll degradation was delayed in fruit previously exposed to 1-MCP then stored in CA. Impacts of 1-MCP and storage environment on concentrations of other 'Golden Delicious' peel constituents increased with storage duration. The results indicate metabolism of apple fruit peel constituents during fruit ripening is differentially regulated by ethylene.