A hot air drying system equipped with real-time computer vision system was used to investigate the effects of drying variables on apple slices color changes. Drying experiments were conducted at drying air temperatures of 50–70◦C,drying air velocities of 1–2 m/s, and samples thicknesses of 2–6 mm. A multilayer perceptron (MLP) artificial neuralnetwork (ANN) was also used to correlate color parameters and moisture content of apple slices with drying variablesand drying time. The effects of drying air temperature and sample thickness on color changes were dominated overthe effect of drying air velocity. However, non-linear and somewhat complex trends were obtained for all color param-eters as function of moisture content. The MLP ANN satisfactorily approximated the color and moisture variationsof apple slices with correlation coefficient higher than 0.92. Therefore, the computer vision system supplementedwith ANN can be used as a non-invasive, low cost, and easy method for fast and in-line assessing and controlling offoodstuffs color and moisture changes during drying.