Effects of pre-treatment methods on lemongrass (cymbopogon citratus) leaf essential oil yield

Abstract

main purpose of this study was to improve the efficiency of hydrodisitllation extraction of lemongrass (Cymbopogon Citratus) leaf essential oil by combining with ultrasonic and Viscozyme L treatments. Lemongrass leaves were treated at different sonication duration (30-120 minutes) or different enzymatic incubation time (30-120 minutes) before running hydrodistillation. The obtained results showed that ultrasonic and Viscozyme L pretreatments increased oil yield, antioxidant capacity and total citral content of lemongrass (Cymbopogon Citratus) leaf essential oil. The maximum oil yields of the ultrasound-assisted hydrodistillation (UAHD) was 1.77 ± 0.12 (g/100 g DW) and the enzyme Viscozyme L-assisted hydrodistillation (EAHD) was 2.30 ± 0.02 (g/100 g DW), corresponding to 120 and 90 minutes of treatments. In contrast, the highest total citral contents were obtained from the 120 min UAHD oil sample (1.32 ± 0.05 mg/ml) and the 90 min EAHD oil sample (0.93 ± 0.03 mg/ml). Meanwhile, the strongest antioxidant capacities were measured from 120 min UAHD and 120 min EAHD oil samples with values of 38.30 ± 0.12 (%) and 59.70 ± 0.13 %, respectively. Key words: lemongrass; hydrodistillation; Viscozyme L; ultrasound; oil yield; antioxidant; citral