NAVEL ORANGE TOLERANCE TO HEAT-TREATMENTS FOR DISINFESTING MEXICAN FRUIT-FLY

Navel orange [Citrus sinensis (L.) Osbeck] was exposed to moist, force d air at 46 degrees C for up to 4.5 hours or 50 degrees C for 2 hours, or immersed for 3 hours in water at 46 degrees C. Quality attributes of heated and nonheated fruit were compared after 4 weeks of storage a t 7 degrees C and 1 week at 23 degrees C. The flavor of oranges immers ed in water was rated significantly inferior to fruit heated in air an d fruit that were not heated. Oranges immersed in hot water also devel oped a higher incidence of decay during storage than oranges heated in air or nonheated control fruit. The flavor of oranges exposed to mois t, forced air at 46 degrees C for up to 4.5 hours was rated by prefere nce panelists as similar to nonheated controls, even though heated fru it had a significantly lower amount of titratable acidity and a higher ratio of sugar to acid. Fruit exposed to high-temperature forced air developed less decay during subsequent storage than nonheated control fruit. Texas 'N33' navel oranges tolerated exposure to forced air at 4 6 degrees C for up to 4.5 hours without deleterious effects on fruit m arket quality.