The effect of ultrasound assisted enzyme pretreatment before distillation on process time, yield and essential oil composition in bay essential oil production

The aim of this study was decreasing the water distillation time of bay essential oil as well as reduction of energy costs and to increasing the essential oil yield. For this purpose, the separate and combined applicability of ultrasound technology and enzymatic extraction methods as a pre-treatment prior to water distillation and also the effects of applied methods on the quality of bay essential oil and process yield were investigated. The water distillation process was carried out with Clevenger apparatus conventionally. Three percent (3 ml/g) essential oil was obtained in 180 minutes by the conventional distillation method. The highest essential oil yield was determined as 3,25 % (ml / g) at 120 minutes in xylanase pretreatment (K) and cellulase pretreatment applied in combination with ultrasound (SU). The same amount of essential oil was obtained in 150 minutes when the ultrasound pretreatment distillation process was applied alone (U20). As a result of GC/MS analysis, 35 components were found in bay essential oil. The main components were determined as 1,8 cineole, alpha terpinen, beta pinene, sabinene and alpha pinene. As a result of treatments, the ratios of 1,8 cineol, alpha terpinen, beta-pinene, sabinene and alpha pinene were ranged between 57,72-60,59 % , 12,52-13,77 % , 2,93-3,25 % , 6,07-6,96 % and 3,44-4,48 % respectively. In the essential oil obtained after cellulase + ultrasound pretreatments (SU), the ratios of sabinene and alpha pinene components were found 11.9 % and 16.9 % respectively which were lower than those of conventional methods (P <0,05). The ratios of the other major components (1,8 cineole, alpha terpinen, beta pinene) were similar to each other. It was also determined that pretreatments which were applied before distillation process shortened processing time and increased the essential oil yield without causing a significant loss in components. Regarding the high cost of continuous usage of enzymes and requirement for the adjustment of pH of distillation water, the ultrasound treatment was determined to be advantageous.