Enzyme kinetics modelling approach to evaluate the impact of high CO 2 and super-atmospheric O 2 concentrations on respiration rate of pomegranate arils.

Super-atmospheric O2has been shown to affect respiration rate (RR), but no model describing its effect on RR for pomegranate arils has been reported. This study investigated the effects of four different gas compositions (5 kPa O2, 10 kPa CO2and 85 kPa N2; 10 kPa O2, 5 kPa CO2and 85 kPa N2; 70 kPa O2, 10 kPa CO2and 20 kPa N2; and air) on RR of pomegranate arils (cv. Wonderful) stored at 5°C. Michaelis–Menten enzyme kinetics models were used to investigate the effect of CO2inhibition on O2consumption rate. Respiratory quotient was used to determine fermentation threshold. The O2consumption rate increased from 0.87 to 2.81 mL/kg h, with increase in O2concentration from 5 kPa to 70 kPa. All enzyme kinetics model parameters adequately described the influence of gas concentration on aril RR with correlation coefficient (R2adj = 81–91%). [ABSTRACT FROM AUTHOR]