An integrated dynamic model of ethylene biosynthesis and respiration of ‘Conference’ pear (Pyrus communis) during storage and shelf life

Respiration and ethylene biosynthesis rates change dynamically in maturing and ripening climacteric fruit. However, typically in modelling work, under low-temperature controlled atmosphere storage, the temporal changes of these metabolic processes have often been neglected. This paper proposes a simplified modelling approach to describe and integrate the temporal changes of respiration and ethylene biosynthesis during storage and subsequent shelf-life. The model starts from transcriptome levels of the involved enzymes and incorporates enzyme synthesis and degradation. The interaction between oxygen and ethylene metabolism at the pathway and signalling level is explicitly incorporated in the kinetic equations. These dynamic models of respiration and ethylene biosynthesis were calibrated using mainly shelf-life data (18 °C in regular air) obtained after storage under various conditions. The models were then validated using data from a storage experiment under standard CA (-1 °C, 3 kPa O 2 , 0.7 kPa CO 2 ) and DCA (-1 °C) conditions in both laboratory and industry settings. The goodness of fit, expressed by the adjusted coefficient of determination R 2 adj , for the coupled model of ethylene and respiration was 0.68. Overall, the model was able to capture the dynamic pattern of respiration and ethylene biosynthesis, aligning acceptably with the measured data in shelf-life. Specifically, the exchange rate of respiratory gases generally increases and stabilises after one week in shelf-life, while the peak of the ethylene exchange rate usually shifts earlier with later shelf-life stages from different storage conditions.