In this article, we study the effects of the temperature control on a dehydration tomato slices process when two control strategies are considered: PID controller and optimal linear control when inherent input time delay is considered. The first controller is tuned by D-partitions method and a numerical procedure in order to minimize a quadratic performance index, the second one considers a state predictor to compensate the effects of the input delayed. The energy savings and the intrinsic characteristics in the tomato slices (vitamin C, total phenols, and lycopene levels) are quantified in order to conclude advantages of the two controllers under study.