Impact of Extraction Methods on Antioxidant and Antimicrobial Activities of Citrus Essential Oils

Abstract

In this study, impact of extraction methods, cold-pressing and vacuum-distillation methods, on yield, chemical composition, antioxidant and antimicrobial activities of citrus essential oils were investigated. The antioxidant activities of citrus essential oils were determined by DPPH scavenging and Ferric thiocyanate assays, while the antimicrobial activities were determined by growth inhibition zone diameter and broth dilution assays against several important foodborne pathogens. The yields of essential oils of Dao lime, PhuTho orange and DoanHung pomelo, extracted by the vacuum-distillation method, were 0.16 %, 0.59 % and 0.04 %, respectively, significantly higher than those extracted by the cold-pressing methods (0.03 %, 0.25 % and 0.03 %, respectively). Total relative concentrations of nine major components of the essential oils extracted by the cold-pressing and vacuum-distillation methods were not significantly different. However, concentration of individual component in the essential oils was changed when using the vacuum-distillation method. Although the essential oils extracted by both cold-pressing and vacuum-distillation methods showed strong antioxidant and inhibition capacities, the antioxidant and antimicrobial activities of citrus essential oils extracted by the vacuum-distillation method were lower than those extracted by the cold-pressing method. As a result, the vacuum-distillation is considered to be the promising innovation theme for producing natural fragrance and essential oil with high production efficiency.