Abstract
Processing watermelon seeds has recently attained great attention in industry from two aspects of snack and high quality oil productions. Hence, in the first phase of our research, studying their drying kinetics, color quality in terms of L* a* b*, total color difference (ΔE), chroma and Hue angle and germination vigor of watermelon seeds were studied experimentally in detail with three drying air temperatures (40, 50 and 60 °C) along with three levels of air velocity (0.5, 1 and 1.5 m s−1). It was concluded that well-known Verma et al. thin layer drying model was greatly superior for prediction of watermelon seed drying kinetics in most cases while the effective moisture diffusivity of seeds was found ranging between 3.009 × 10−10 and 6.805 × 10−11 m2 s−1 and the energy of activation was evaluated between 37.11 and 56.63 kJ mol−1. It was also inferred that air temperature level more profoundly affected the color and germination of the seeds than velocity while to maintain color quality and germination vigor high, the convectively drying temperatures should not exceed 50 °C.
