The influence of the process parameters on the drying kinetics of different food products, fruits and vegetables, using different dryers was investigated. The dehydration kinetics of samples was determined by continues recording of mass changes, temperature profile of material and drying media as well as moisture profile using computer process control. To speed up the dehydration kinetics, and to eliminate the enzymatic browning activity as well as non enzymatic changes during dehydration process different physical and chemical procedures of samples pre-treatment were applied, depending on method used, related technical solutions were proposed. Evaluation of each method and the influence of the process parameters on the properties of dried materials were performed using standard analytical methods: thermo-gravimetric, rehydration, colorimetric, volumetric and high pressure liquid chromatography – HPLC. The changes in colour and volume as well as rehydration rate (reconstitution characteristic) for each of the drying methods were studied. After defining the optimal drying process parameters, different pre-treatment methods were investigated. The existing mathematical models (thin-layer equations) were tested and new semi-empirical models that describe drying processes of fruits and vegetables using different driers were defined. When modelling the experimental data for apricot and apple samples which were dried in the tunnel dryer at drying temperatures of 50 °C, 60 °C, 70 °C and 80 °C and air flow velocities of 1,4 m s-1; 2,1 m s-1 and 2,8 m s-1, Midilli–Kucuk model proved to be the best and showed a good agreement with the experimental data. A new semi-empirical models were developed for the simulation of apricot and apple drying at temperature range 50–80 °C and velocity range 1,4–2,8 m s-1 of drying air. Furthermore, the influence of the drying temperature and drying methods on the content of the main nutritive components was studied. The degradation of β – carotene was the smallest when non-treated carrot samples were dried in the tunnel dryer (TD) at temperature of 70 °C and at airflow velocities of 2,8 m s-1. The highest rehydration ratio was observed when apricot samples were dried at temperature of 80 °C and airflow velocities of 1,4 m s-1. The best results (good rehydration ratio and colour) were achieved when apple samples were dried in the tunnel dryer (TD) at temperature of 50 °C. As for carrot and parsley root samples, the best results were achieved when drying in the tunnel dryer (TD) at temperature of 60 °C and airflow velocities of 2,8 m s-1. The influence of the different sample pre-treatment procedures on the drying kinetics and the properties of dried materials was determined.