Modeling respiration rates of Ipomoea batatas (sweet potato) under hermetic storage system

Abstract

The sweet potato respiration rate versus gas composition was mathematically modeled, as required to design an effective modified atmosphere packaging (MAP) system. Storage tests of sweet potato were conducted at 15-30 degrees C. The O-2 and CO2 concentrations were measured over time in a closed system. The respiration rate was estimated to be a derivative of the quadratic function of gas concentration over time and decreased with decreasing O-2 and increasing CO2. The model of the uncompetitive inhibition enzyme reaction rate fitted well with the experimental results. The temperature dependency of the equation parameters (V-m, K-m, and K-i) followed the Arrhenius relationships. The use of the proposed models to simulate the respiration rates as a function of temperature revealed less temperature dependence in low O-2 and high CO2 concentrations. This gas composition, more desirable in practice, also agreed with the typical gas composition of MAP.