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The main aim of this work is to study the main factors affecting the quality of the dried product and the energy requirements through optimizing these factors. To achieve that different drying systems (solar, hybrid solar and oven dryings), layers thickness (1, 2 and 3 cm) and drying temperatures (50, 60 and 70 °C) were used. The obtained results indicated that, the accumulated weight loss of marjoram leaves ranged from 73.22 to 76.9%, for all treatments under study. The moisture content of marjoram leaves ranged from 273.39 to 333.17, 258.02 to 333.04 and 269.38 to 324.90% d.b. for hybrid solar, oven and solar drying systems, respectively. The highest value of the drying rate of marjoram leaves (223.73 gwater kg−1 h−1) was obtained when the marjoram dried by oven drying system at 70 °C at 1 cm layer thickness. The highest values of the basil and marjoram oil content (2.91%) was obtained when the marjoram dried under sun drying system. The energy consumption for drying marjoram decreases with increasing drying temperature and layer thickness for hybrid solar and oven drying systems. The cost of dried marjoram dried under hybrid solar drying system was lower than those of oven drying system, the highest cost (13.48 LE kg−1) was obtained at a temperature of 50 °C and a layer thickness of 1 cm. [ABSTRACT FROM AUTHOR]

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 gwater 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. [ABSTRACT FROM AUTHOR]

Energy scarcity and conventional energy problems are the main reason of finding a renewable source of energy which is cheap and environmental friendly, therefore, biodiesel production is one of the most promising solutions of this problem. Also, Egyptian castor is one of the most important crops for oil production compared with other commonly used oil crops. The main aim of this study is to enhance the production of bio-oil from Egyptian castor seeds by using microwave and ultrasonic as pre-treatments. To achieve that, the effects of extraction screw speed (20, 40 and 60 rpm) and temperature (100, 150, 200 and 250 °C) on oil extraction yield and quality, extraction energy requirements and extraction time and were studied. Also, the effect of pretreatment conditions of microwave at three levels of power (Low, Med and High) and different times (1, 2 and 3 min) and pretreatment condition ultrasonic with different temperatures (40, 60 and 80 °C) and different times (15, 30 and 45 min) for castor seeds before extraction with the optimum condition of the screw press on oil extraction yield from castor seeds, extraction energy, extraction time and quality of the oil extracted. The results indicate that the optimum conditions oil extraction by screw press were 200 °C extraction temperature and 60 rpm screw speed. It could be seen that the extraction oil yield, extraction energy requirements and extraction time were 35.59%, 18.68 and 1.86 min, respectively. Microwave pretreatments had better on oil yield and energy required for extraction compared to ultrasonic pretreatments, where, microwave pretreatments recorded high oil yield and lower energy requirements compared to the ultrasonic pretreatments. Oil yield ranged from 32.67 to 37.41% compared to 13.29 to 39.83% in literature. The time required for extraction was ranged from 1.77 to 2.00 and 1.79 to 2.21 min for microwave and ultrasonic pretreatments, respectively. The pretreatment improved properties of the extracted oil. [ABSTRACT FROM AUTHOR]