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To investigate a flesh browning (FB) disorder in Pink Lady apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. cv. Cripps Pink], fruit were harvested from the same orchard each year from 2002 to 2005, at two or three maturity stages each year. Fruit were kept in air or controlled atmosphere (CA) storage (1.5- to 2-kPa O2 in combination with 1-, 3-, or 5-kPa CO2) at 0.5 °C. Additional subsets of fruit were exposed to 1 μL·L−1 1-methylcyclopropane (1-MCP) for 24 hours and dipped in 2200 μL·L−1 diphenylamine (DPA) for 5 min or held in air at 0.5 °C for 2 or 4 weeks before CA storage. Flesh browning was not seen in air-stored fruit but appeared in CA-stored fruit as soon as 2 months after harvest. Flesh browning incidence did not increase after longer storage times. Flesh browning increased with increasing CO2 concentration and decreasing O2 concentration in storage. 1-MCP did not significantly affect FB incidence, while delaying CA by 2 or 4 weeks reduced it. Diphenylamine eliminated FB incidence. When similar storage atmospheres were compared for the four seasons, FB incidence was high in 2002 and 2004 and low in 2003 and 2005. Concentrations of B, Ca, and Mg in apple flesh and seasonal field temperatures during the growing and harvest periods were related to FB incidence in 2002, 2003, and 2004 but not in 2005. The relationship of these pre- and postharvest factors to FB susceptibility are discussed.

Peel browning of 'Bartlett' pears (Pyrus communis L) caused by various mechanical injuries during postharvest handling results in a reduction in visual quality. Various commercial and experimental coatings and antioxidants with potential to reduce peel browning of pears have been evaluated. Treatment with 0.2% diphenylamine (DPA) or 0.3% ethoxyquin (Eth) reduced peel browning on 'Bartlett' pears induced by vibration, rolling or scuffing. However, this effect only lasted for about 5 days when treated pears were stored at 0 • C. For the consideration of practical use, pears would have to be treated and packed shortly before transport to achieve a reduction in peel browning. DPA and Eth did not reduce peel browning on pears induced by handling at 20 • C after treatment. It is suggested that tight-fill packaging and use of DPA or Eth would best reduce peel browning.

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