The effect of modified atmospheres on the rate of firmness change in 'Braeburn' apples

Gas exchange rates and softening of 'Braeburn' apples were measured under a range of modified atmosphere conditions to characterise their functional relationship. Both gas exchange (measured as CO2 production) and softening were maximally suppressed at around 1-1.5 kPa O-2. At these low O-2 levels, CO2 had no effect on the rate of softening. Both softening and gas exchange had comparable Kin values indicating a common kinetic background. The integrated approach revealed a close quantitative relationship between rate of softening and rate of gas exchange of 'Braeburn' apples indicating that fruit softening is directly metabolically linked to gas exchange. Due to the less efficient character of fermentation. the softening of 'Braeburn' apples related more closely to respiration than to fermentation. (C) 2001 Elsevier Science B.V. All rights reserved.