Tracking the development of the superficial scald disorder and effects of treatments with diphenylamine and 1-MCP using an untargeted metabolomic approach in apple fruit

Superficial scald is a physiological storage disorder that significantly reduces the marketability of apple fruit. To gain fundamental knowledge about the biochemical pathways leading to the development of the disorder and mechanisms of treatments for prevention, an untargeted metabolomics experiment employing liquid chromatography and mass spectrometry with data independent acquisition was performed. Metabolomic changes of two apple cultivars ‘Cortland’ and ‘Red Delicious’ with scald development and scald control treatments, using diphenylamine and 1-MCP, at 0–1 °C for up to 7 months was investigated. In total, 833 features/compounds were analyzed, and among them 59 were found to change significantly in controls involved in scald development, and in response to DPA and 1-MCP treatments. Our results provide new evidence that metabolites in association with phenylpropanoid metabolism, antioxidant and redox systems, and amino acid metabolism are related closely to scald development and response to potential treatments.