QUALITY OF PINK LADY ® BRAND APPLE
Apple (Malus domestica Borkh, ‘Pink Lady ® brand’) fruit were harvested from one California orchard in 2002, 2003 and 2004 at two or three different maturity stages each year. Fruit were evaluated for background color, firmness, fruit size, percentage of blush, starch index (CTIFL chart), soluble solids, titratable acidity and carbon dioxide (CO2) production and immediately stored at 33 oF in air or in controlled atmosphere (CA). In 2003, additional treatments included 1 ppm of SmartFresh ® (1-MCP) or 2200 ppm of diphenylamine (DPA). Firmness, CO2 production, external condition and internal browning were determined after storage in CA or air and 5 days at 68 oF. Fruit stored in CA conserved higher firmness and produced less CO2. Internal browning was not seen in fruit stored in air, but appeared in fruit after two months storage in CA. The incidence did not increase after longer storage times. SmartFresh ® worked as well as CA in conserving the quality of the fruit. It did not affect the incidence of internal browning, but DPA inhibited internal browning completely. When comparing similar storage atmospheres for all three seasons, the incidence of internal browning was significantly different, being much higher in 2002 and 2004. A mineral analysis of the apple flesh showed differences among the seasons. Concentrations of calcium (Ca), boron (B) and magnesium (Mg) were significantly higher in 2003, corresponding with a lower incidence of internal browning.
Responses of early, mid and late season apple cultivars to postharvest application of 1-methylcyclopropene (1-MCP) under air and controlled atmosphere storage conditions
The potential for commercial application of 1-methylcyclopropene (1-MCP) to maintain quality of ‘McIntosh’, ‘Empire’, ‘Delicious’ and ‘Law Rome’ apples under air and controlled atmosphere (CA) storage conditions was investigated. These cultivars represent early, mid and late season apples with ripening rates ranging from fast to slow. 1-MCP gas concentrations used were 0.5, 1 and 2 m ll 1 , generated from measured amounts of Ethylbloc™ powder. Fruit of each cultivar were removed from storage at 6 week intervals during 30 weeks in air, or at 8 week intervals during 32 weeks in CA, and evaluated after 1 and 7 days at 20°C. Effects of 1-MCP were greater in CA than air storage. A dose response of internal ethylene concentrations and flesh firmness to 1-MCP was found in ‘McIntosh’ and ‘Law Rome’, but ‘Delicious’ and ‘Empire’ ripening was generally prevented by all 1-MCP concentrations. 1-MCP reduced superficial scald incidence, and accumulations of a-farnesene and conjugated trienols during air storage. The results indicate that the efficacy of 1-MCP is affected by cultivar and storage conditions, and that successful commercial utilization of the chemical will require understanding of these relationships. © 2000 Elsevier Science B.V. All rights reserved.
Postharvest studies of resistance to gas diffusion in McIntosh apples
Abstract Low oxygen injury (LOI) in controlled atmosphere (CA) storage was positively correlated with fruit resistance to gas diffusion (R) at harvest in the McIntosh cultivar of apples ( Malus domestica Borkh). In contrast to early harvest, late harvest resulted in lower R at harvest and after storage. The longer the apples were held in CA storage, the lower was R. R was negatively correlated with whole fruit volume after storage, but not at harvest. R was negatively correlated with respiration rate at harvest, when respiration and R were high, but not after CA storage, when respiration rate and R were low. R increased and fruit volume decreased during storage at 80% relative humidity (RH), whereas the opposite occurred in a high RH (> 95%) environment. In comparison with other strains of McIntosh, Marshall McIntosh had higher R and enhanced susceptibility to LOI. And, at the same concentrations of fruit internal O 2 , Marshall McIntosh accumulated ten-fold more ethyl alcohol than did Rogers McIntosh, which indicated different thresholds for anaerobiosis in these two strains.