Evaluation some of quality characteristics during drying of watermelon seeds

Drying is one of the most common techniques for agricultural production processing which improves shelf life of the final product. The drying experiments were conducted in a laboratory cylindrical non continuous rotary dryer equipped with automatic temperature and full rate control devices. Drying temperatures from 30 °C to 65 °C and occupancy rate between 25 to 66 % were assessed in the process. In this study the effects of hot air drying temperature (30, 45 and 60°C), and occupancy rate (25, 50 and 75 %) at constant air velocity (0.8 m/s) on failure force, color of watermelon seeds, sensory attributes (color), germination rate on the samples and energy consumption were investigated. Results showed interaction effect of the two factors (temperature and fulling rate hopper) was significant on germination rate samples, energy consumption dryer and color parameter (a). Temperature effect on all measured traits and also the effect of fulling rate hopper were significant for all traits except failure force in vertical load direction. Dried samples at 30°C with 50% fulling rate hopper had the highest percentage of germination with cylindrical dryer. The highest value of color parameter (a) occurred in the condition of temperature 45°C with 50% fulling rate hopper. In each one of drying temperature, with increasing fulling rate hopper, energy consumption for drying the samples increased. Optimal temperature and fulling rate hopper for drying watermelon seed for providing market (nuts) and seed consumption with cylindrical dryer, the samples should be dried at 60°C with 25% fulling rate hopper, and 30°C with 50% fulling rate hopper respectively.