Carbon Dioxide-induced Flesh Browning in Pink Lady Apples

Abstract

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.