Respiration rate and ethylene metabolism of 'Jonagold' apple and 'Conference' pear under regular air and controlled atmosphere.

The 1-aminocyclopropane-1-carboxylate (ACC) oxidase activity, ethylene production, CO₂ release and O₂ uptake of 'Jonagold' apple and 'Conference' pear were investigated during regular air and controlled atmosphere storage. Storage conditions tested at 0 °C during 6 months, with a further 10 d shelf-life in air at 20 °C were: 0.5 kPa O₂ + 6.0 kPa CO₂; 3 kPa O₂ + 6 kPa CO₂; 1 kPa O₂ + 3 kPa CO₂; 1.5 kPa O₂ + 1.5 kPa CO₂; 0.5 kPa O₂ + 0.5 kPa CO₂ and 2 kPa O₂ + 1 kPa CO₂. Apple and pear kept in regular air showed higher ACC-oxidase activity, ethylene production and respiration rates. Under controlled atmosphere, lower O₂ and/or higher CO₂ partial pressures strongly inhibited ACC-oxidase activity and ethylene production of apple and pear. Agreeing with ACC-oxidase activity and ethylene production, respiration rate was affected by the controlled atmosphere in a similar manner. The controlled atmosphere condition of 0.5 kPa O₂ + 6.0 kPa CO₂ showed the strongest suppression in ethylene production, respiration and generated higher values in the respiratory quotient. However, fruit metabolism was strongly suppressed in 'Jonagold' than in 'Conference', persisting a strong residual effect of controlled atmosphere during the full 10 d shelf-life in apple. [ABSTRACT FROM AUTHOR]