Numerical simulation of vitamin C degradation during dehydration process of fresh tomatoes

In this study, the kinetics of vitamin C degradation is simulated by the development of a model based on the numerical approach of heat and mass transfer processes and the degradation rate of vitamin C during the dehydration of tomato slices at 45, 60, and 75 degrees C. The results achieved by experimental data were consistent with those obtained by the numerical model (R-2 > 0.88 and RMSE < 0.27). So, it is concluded that the rate of vitamin C degradation was increased at the beginning of the dehydration process when the temperature of the inner sample layers was raised and then its value decreased with the reduced moisture content at the stable temperature conditions. During the dehydration process, the highest concentrations of vitamin C were obtained at the surface layer of the tomato slice with the least moisture content and the lowest of its value was obtained at the sample center with the highest moisture content. Practical Applications Some of the essential nutrients are degraded during the dehydration process. Understanding factors effective on nutrient degradation is important to optimize the dehydration conditions to produce healthy food. Since vitamin C is an indicator for determining the health food, modeling of its degradation kinetics is an efficient method for understanding the effective factors of retaining nutritional components during the dehydration operation. In this research, a novel method developed to simulate the vitamin C degradation in different layers of a tomato slice during a thermal process. The result of this method is used to interpret the factors affecting on degradation of food component. After the dehydration process, the concentration of vitamin C at the surface node was approximately 47.9, 22.1, and 9.9% higher than its value at the center node at 45, 60, and 75 degrees C, respectively. The effective moisture diffusivity was the most sensitive parameter in the modeling of vitamin C degradation kinetics.