Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2006
Publication Date: N/A
Interpretive Summary: Superficial scald ("scald") is a market limiting disorder of apples that results in discoloration of the peel. Although commercially available methods to control scald exist, a clear understanding of the process of scald development remains to be developed. The present study evaluated how the chemical structure of diphenylamine (DPA), a material used to prevent scald, is altered during scald development. The results indicated postharvest technologies can influence DPA metabolism by apple fruit, but that accumulation of specific DPA metablites do not appear to be associated with scald development.
Technical Abstract: Diphenylamine (DPA) is used for superficial scald control in apple fruit. A number of DPA derivatives resulting from C-nitration, C-hydroxylation, O-methylation and N-nitrosation can be present in DPA-treated apple fruit after storage. The presence of the compounds may be indicative of metabolic processes leading to scald development. Therefore, apple peel DPA and DPA derivative content in fruit treated at harvest with DPA or DPA plus 1-methylcyclopropene (1-MCP) was assayed upon removal of fruit from controlled atmosphere (CA) and regular atmosphere (RA) storage and during a 14-day post-storage ripening period. Post-storage ripening, 1-MCP treatment, and CA storage had varied affects on DPA derivative content suggesting reactive oxygen or nitrogen species, such as .OH, .NO, and .NO2 or enzyme catalyzed reactions may be present during certain ripening and senescence related physiological processes. Correlations between scald incidence and content of specific derivatives were not observed.