Research on drying techniques to obtain berry oil from laurel (Laurus nobilis L.)

In this research, three steps oil producing method was studied to increase the laurel berry oil which is gained by traditional method. The new concept is consisting of three main steps. These are; drying, screw pressing (mechanical press) and solvent extraction. To obtain laurel berry oil by screw pressing technique the moisture content of the berries should be reduced till to 7-9 % (w.b.). To achieve this, laurel berries were dried by hot air drying method that applied in atmospheric and vacuum conditions and microwave and infrared drying methods. In frame of this study drying parameters, oil yield, oil composition, physical and mechanical properties of dried berries were investigated. The optimum drying temperature for hot air drying were 80 ºC where 960 min of drying time was obtained. The drying times were 720 minutes under 0,1 atm of vacuum at 80 ºC. In case of using microwave belt dryer with energy supply of 800 W where the band speed of 6,8 mm/s and air flow rate of 2,30 m/s were used, a drying time of 13,15 minutes was recorded. Infrared drying on semi opened ventilation mode gave a drying times of 720 minutes.