The Influence of Breaks in Storage Temperature on 'Cripps Pink' (Pink Lady™) Apple Physiology and Quality

The maintenance of optimal storage conditions for fresh produce is rarely achieved in commercial cool chains. The impact of deviations for short time periods from these optimal storage conditions on fruit quality has not been thoroughly investigated. In this study, 'Cripps Pink' apples (Malus domestica) stored at 0 8C in air were exposed to periods at 20 8C (for1, 3, and 6 days)to simulate breaks in the cool chain. The influence of harvest maturity, storage time before exposure, length of exposure, and multiple expo- sures to 20 8C on fruit physiology during and after the exposures was monitored through 27 laboratory-based scenario simulations. Preclimacteric apples exposed to 20 8C has- tened climacteric development, whereas postclimacteric apples were induced to produce ethyleneat '1.5timesthenormalonreturntocoolstorageat0 8Cirrespectiveofthefruit harvest maturity or timing, length, and number of exposures to 20 8C. The observed increase in ethylene production did not increase rates of reduction of either fruit stiffness (a measure offlesh texture) or background color measurement (hue angle). This research suggests that fluctuations in temperature have a greater effect in terms of changes in quality for preclimacteric apples than postclimacteric fruit. The reasons why changes in fruit stiffness and background hue angle in postclimacteric fruit did not respond to increases in ethylene production require further investigation.