Modeling respiration characteristics of pear (Dargazi) accompanied by platyrachis S. coating to design modified atmosphere package

In this study effect of temperature, O2 concentration and storage time were investigated on respiration rate of uncoated and coated pear (Dargazi Cultivar) using Sclerorhachis platyrachis essential oil of 0, 125, 250, and 500 ppm. Mathematical model using Michaelis–Menten’s equation, with the model constants described by means of an Arrhenius-type relationship was applied to predict respiration rate at various temperatures (4, 10, and 25 ºC) and O2 concentrations to design modified atmosphere packaging (MAP) of pear in order to extend its shelf-life. Results showed that all factors affected respiration rate of the pears but the influence of temperature was most pronounced. Increase in temperature led to increase of respiration rate and reduction of positive effect of essential oil on this parameter reduction. Moreover, after about 100 hours, respiration reached equilibrium. Respiratory quotient of Pears at 4 and 10 °C was on aerobic limit. However, at 25 °C, after 110 hours, and reaching CO2 to 23%, respiratory quotient passed the critical point. Finally, package containing 3.7% O2 + 8.1% CO2 + 88.2% N2 was suggested as an appropriate MAP for storing the pears (Dargazi cultivar).