Effect of loading rate and source of energy on the drying parameters of the basil during drying

The basil leaves were dried different sources of energy at different loading rates. Using hybrid solar drying compared to the conventional source of energy such as fossil and propane. Drying parameters were studied. Also, product quality was assessed under study treatments. The results indicated that the higher accumulated weight loss of basil leaves (75.56%) were obtained at 25 kg m^-2 loading rate and solar drying system. The highest rate of the decrease in moisture content of basil leaves was happened at the 45 kg m^-2 loading rates. Meanwhile, the lowest rate of the decrease in moisture content of basil leaves was found at 15 kg m^-2 loading rates. The highest drying rate of basil leaves (219.54 g_water kg^-1 h^-1) was obtained at the loading rate of 15 kg m^-2. The highest values of total chlorophyll and color of basil leaves 745.9 and 36.35 were found for solar dryer. The lowest values of total chlorophyll and color of basil leaves 703.5 and 31.66 were found for diesel dryer. The drying efficiency ranged from 33.98 to 40.33% for all batch loads. The highest essential oil yield obtained for solar dryer, the lowest essential oil yield occurred for diesel dryer. The highest value of volatile compounds with found for solar dryer. The total costs for basil drying were 19.73, 26.70 and 23.93 LE h^-1 for solar, diesel and propane dryers, respectively. Also, the total costs of basil drying were 8.77, 13.15 and 12.27 LE kg^-1 dried for solar, diesel and propane dryers, respectively.