Loss of heat tolerance in 'Kensington' mango fruit following heat treatments.
Jacobi K. K., MacRae E. A., Hetherington S. E.
Author Affiliation: Gatton Research Station, Queensland Horticulture Institute, Locked Mail Bag 7, M/S 437, Gatton 4343, Qld, Australia.
Postharvest Biology and Technology 21 : 321-330
Abstract : Conditions that promote loss of heat tolerance, or dehardening, of 'Kensington' mango fruit (Mangifera indica) were investigated. Fruit were conditioned at 40°C for 8 h, and then placed at 22°C (dehardened) for 8, 16, 24, or 48 h prior to hot water treatment (HWT) (47°C held for 15 minutes). The greatest reduction in fruit heat tolerance occurred in fruit placed at 22°C for 16 h. Compared with the other conditioned fruit, these fruit had the highest incidence and severity of skin scalding, external cavities, starch layer, increased F0 values and a lack of recovery in FV/FM ratios after HWT. It was concluded that the loss of heat tolerance in 'Kensington' fruit occurred at a slower rate than the increase in heat tolerance brought about by the 40°C conditioning treatments. Exposure of fruit to 22°C for 24 h or longer accelerated fruit ripening, and induced some protection against heat injury.