Modified atmosphere package design of minimally processed broccoli

The aim of this work was to study the effect of the oxygen, carbon dioxide and temperature on the respiration rate of minimally processed broccoli in order to design a modified atmosphere package. The respiration rate of minimally processed broccoli were determined in a modified closed system at 5, 7, 15 and 20°C with 2, 5, 10, 15 and 21% of oxygen and nitrogen as balance and 0, 10, and 20% of carbon dioxide in air at 15°C. The effect of temperature was also studied on product conditioned at 3%O2 and 15% CO2. Michealis and Menten and Arrhenius model were used to describe the effect of independent factors on product respiration rate. The maximum respiration rate estimated at reference temperature was 90±20 ml kg-1 h-1, the Km value (the oxygen concentration at the average of the maximum respiration rate) was 1.65 ±0,04, and the Kmc value was 1.9 (R2=0,99). Activation energy (Ea) of the respiration rate process was estimated at 81 kJ mol-1. Results highlighted that the model is appropriate to design MAP for minimally processed broccoli, but validation at more temperature must be performed. Moreover, the time to reach equilibrium inside the pack must be optimize to assure that the package extend the product shelf life.