Kinetic Modeling of Vitamin C Degradation in Lettuce (Lactuca sativa L) under Room and Cold Temperatures Using Computer Simulation Analysis

This study investigates the kinetic modeling of vitamin C degradation in lettuce under room and cold temperatures of 17.5 °C, 19.5 °C, 21 °C and 6.5 °C, 7.5 °C, and 9.5 °C respectively using computer simulation analysis. High-Performance Liquid Chromatography is employed to assess the vitamin C concentrations in the lettuce samples, utilizing an isocratic elution procedure of flow rate of the mobile phase at 1.2cm3 min-1 and an injection volume of 20 µL. The temperature of the analytical column is kept constant at 25 °C coupled with ultraviolet-visible detection set at 245 nm. The lettuce kept at room and cold temperatures for nine days show a reduction in vitamin C with increasing temperature and time. The degradation of vitamin C followed a first-order kinetic model as the average coefficient of determination (R2-value) for room and cold temperatures tending to 1: 0.922843 and 0.940793 respectively. The integrated law method of first order kinetics gave rate constants of 0.855, 0.925, 0.991 and 0.497, 0.51, 0.546 k (min-1) for the room and cold temperatures with corresponding half-lives of 0.8107, 0.7493, 0.6994 and 1.3947, 1.3591, 1.2695 days respectively. A mathematical model is created on the computer and the model's behavior is explored by running the simulation (forecast). The predicted kinetic models formulated gives the best prediction at ln(C) = ln(C0) - 0.497t. The activated energy (EA) yielded values of 10.2220 and 30.4706 kcal/mol for both temperatures respectively. The experimental and computer simulation analysis indicates that lettuce at 6.5 °C retain higher vitamin C concentration.