Dynamic changes in volatile profiles and non-volatile metabolites of postharvest Cara Cara oranges induced by gamma irradiation

This study investigated the effects of gamma irradiation (GI) at a dose of 0.6 kGy on the dynamic changes of volatile and non-volatile compounds in Cara Cara oranges during postharvest storage. Sixty-one volatile components were identified, with total relative concentrations ranging from 2465.89 to 5785.54 μg/L. Limonene, linalool, ethyl butyrate, ethyl 2-methylbutyrate and nerolidol were identified as key aroma-active compounds in fresh Cara Cara oranges. The application of GI treatment reduced limonene content and enhanced esterification, promoting ethyl butyrate and ethyl 2-methylbutyrate as dominant aroma contributors in stored fruit. The GI treatment significantly reduced the fruit damage rate and MDA content while enhancing antioxidant capacity in Cara Cara fruit during prolonged storage. Through a widely targeted analysis, 134 differential non-volatile metabolites were annotated in the KEGG pathway. Elevated levels of key metabolites and the increased activity of rate-limiting enzymes (PFK, PAL, 4CL, ACC, SDH, and MDH), suggested GI might potentially accelerate metabolic flux in postharvest Cara Cara oranges. Overall, this study indicated that GI treatment could effectively reduce postharvest damage in Cara Cara oranges while modulating flavor profiles and metabolic responses.