Chemical and quality traits of 'Olinda' and 'Campbell' oranges after heat treatment at 44 or 46 °C for fruit fly disinfestation

Post-treatment levels of ethanol in both cultivars were significantly higher than in non-treated fruit. During storage and SMP, significant increases of ethanol were detected in control fruits with respect to their initial levels, whereas a reverse trend occurred in fruit subjected to heat treatment. Upon termination of the heat treatment at 44 or 46 °C, mean taste scores of 'Olinda' oranges were lower than those of untreated fruit, while the taste of 'Campbell' oranges was adversely affected only by the 46 °C treatment. After storage and SMP, taste differences between treated and control fruit were not significant. Flavour scores were unaffected by the treatment at 44 °C. Following treatment at 46 °C flavour rating in 'Olinda' fruit was significantly lower than control fruit while after storage and SMP the differences in flavour scores between treated and untreated fruit were non significant. Heat treatment to a fruit core temperature of 44 °C for 100 min or 46 °C for 50 min can thus have important commercial applications as an alternative to toxic chemical fumigants or to longer and more expensive disinfestation treatments such as cold quarantine.