Effect of fruit maturity on the response of 'Kensington' mango fruit to heat treatment.
Jacobi K. K., MacRae E. A., Hetherington S. E.
Author Affiliation: Queensland Horticulture Institute, Gatton Research Station, Locked Mail Bag 7, M/S 437, Gatton, Qld 4343, Australia.
Australian Journal of Experimental Agriculture 41 : 793-803
Abstract : The effects of conditioning and hot water treatments on immature and mature mangoes cv. Kensington were examined. A hot water treatment of 47°C fruit core temperature held for 15 minutes increased weight loss (50%), fruit softness (15%), disrupted starch hydrolysis and interacted with maturity to reduce the skin yellowness (40-51%) of early harvested fruit. Immature fruit were more susceptible to hot water treatment-induced skin scalding, starch layer and starch spot injuries and disease. Conditioning fruit at 40°C for up to 16 h before hot water treatment accelerated fruit ripening, as reflected in higher total soluble solids and lower titratable acidity levels. As fruit maturity increased, the tolerance to hot water treatment-induced skin scalding and the retention of starch layers and starch spots increased and susceptibility to lenticel spotting decreased. A conditioning treatment of either 22° or 40°C before hot water treatment could prevent the appearance of cavities at all maturity levels. The 40°C conditioning temperature was found to be more effective in increasing fruit heat tolerance than the 22°C treatment; the longer the time of conditioning at 40°C, the more effective the treatment (16 vs 4 h). For maximum fruit quality, particularly for export markets, it is recommended that mature fruits are selected and conditioned before hot water treatment to reduce the risk of heat damage.