The influence of pre-storage delayed cooling on quality and disorder incidence in 'Honeycrisp' apple fruit

The influence of a pre-storage, 7-day, 20degreesC warming period on post-harvest apple (Malus xdomestica Borkh.) fruit quality and disorder expression-soft scald and low temperature breakdown in particular, were investigated in 'Honeycrisp' fruit grown in the Annapolis Valley of Nova Scotia. The apples from 7-year old trees were harvested from three commercial sites on Sept 30, 2002 (early) and Oct 10, 2002 (late), after which, half of the fruit was immediately cooled to 5 degreesC (control), while the other half was held for 7 days at 20degreesC (delayed cooling treatment). Both the control and delay cooled apples were then stored at either 3 or 5 degreesC in controlled atmosphere (CA) (2.5 kPa O-2; 1-1.5 kPa CO2) or refrigerated air (RA) storage for 4 and 6 months. Fruit quality measurements and disorder incidence were recorded following storage removal and a 7-day shelf-life at 20degreesC. Delayed cooling had no effect on fruit firmness, soluble solids (%), titratable acidity, epidermal greasiness, senescent breakdown, and bitter pit (the incidence of these latter disorders was low), while moisture loss from the delay cooled fruit ranged from 1.2 to 1.3% following the 7-day treatment. Delayed cooling strongly suppressed the development of the storage disorders soft scald and low temperature breakdown, which in the control fruit reached upwards to 30% of the sample. No CA- or RA-related differences in these disorders were observed in the fruit receiving the pre-storage delayed cooling treatment. Storage rot was not influenced by delayed cooling and was present in upwards to 32% of the fruit from the late-harvested apples after 6 months of storage. In regions where soft scald and low temperature breakdown are serious postharvest problems, it appears that a delayed cooling period prior to storage will help minimize economic loss. Crown Copyright (C) 2004 Published by Elsevier B.V. All rights reserved.