Respiration rate and ethylene metabolism of ‘jonagold’ apple and ‘conference’ pear under regular air and controlled atmosphere

Abstract

The 1-aminocyclopropane-1-carboxylate (ACC) oxidase activity, ethylene production, CO2 release and O2 uptake of ‘Jonagoldʼ apple and ʻ‘Conferenceʼ 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 ʻConferenceʼ, persisting a strong residual effect of controlled atmosphere during the full 10 d shelf-life in apple.