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 1–2m/s, and samples thicknesses of 2–6mm. A multilayer perceptron (MLP) artificial neural
network (ANN) was also used to correlate color parameters and moisture content of apple slices with drying variables
and drying time. The effects of drying air temperature and sample thickness on color changes were dominated over
the effect of drying air velocity. However, non-linear and somewhat complex trends were obtained for all color parameters
as function of moisture content. The MLP ANN satisfactorily approximated the color and moisture variations
of apple slices with correlation coefficient higher than 0.92. Therefore, the computer vision system supplemented
with ANN can be used as a non-invasive, low cost, and easy method for fast and in-line assessing and controlling of
foodstuffs color and moisture changes during drying