optimum conditions for drying pomegranate arils in a solar dryer using surface response method

this study determined optimum conditions for drying pomegranate arils in a solar dryer. a cabinet solar dryer was used in active and mixed modes. the response surface method was employed with nine treatments (runs) and a control run (3 m/s air velocity and 2 cm in thickness) and five replications. the bryte cultivar was tested and samples were dried to approximately 10% moisture. drying time, vitamin c, color, acidity, and microorganisms were evaluated in the samples. the effects of thickness and air velocity on drying time and all qualitative factors were significant except for acidity and taste (p < 0.05). drying time, yellowness (b factor in color) and microorganisms increased as thickness and air velocity increased. brightness (l factor in color), redness (a factor in color), and vitamin c decreased with as thickness and air velocity increased. the quality of the dried products in the solar dryer was much better compared to the sun-dried control samples. samples 0.6 cm in thickness with 3 m/s air velocity had the best quality in the solar dryer. their drying time decreased 85% in comparison with sun drying.