Antibacterial and antioxidant activities of essential oil extracted from lime leaves using enzyme - assisted vacuum extraction method

Abstract

Essential oils (EOs) are natural compounds containing complicated biologically active substances, and they are being used as flavoring agents, as also preservative agent in food technology. This study was conducted to determine the antioxidant and antimicrobial activities of EOs extracted from leaves of three citrus varities. Leaves of Long An lime (Citrus aurantifolia Swingle), Da Lat lime (Citrus limonia Osbeck) and Dao lime (Citrus hybrid – Citrus spp.) were extracted by enzymeassisted vacuum distillation. The obtained results showed that Viscozyme L pretreatments increased oil yield. The antioxidant activities of EO were measured by Ferric Thiocyanate assay and 2,2-diphenyl–1-picrylhydrazyl (DPPH). Two kinds of EO showed high antioxidant activities are Long An lime leaf and Da Lat lime leaf. The antimicrobial activities were tested by diffusion and dilution method against the foodborne microorganisms. The activity of Long An lime leaf EO was stronger than that of Dao lime EO and Da Lat lime EO on S. aureus, B. cereus, S. typhi. However, in case of P. aeruginosa, the inhibition of Dao lime EOs was stronger than that of Long An lime EO and Da Lat lime EO. According to the reults, EOs extract from different leaves of Citrus varieties may have different antimicrobial and antioxidant activities. The results of this study showed that essential oils of citrus leaves using enzyme- assisted vacuum extraction method could be developed to be used in industrial application and the citrus essential oils could be widely used as flavoring and preservatives in food, cosmetic and pharmaceutical industries. Key words: Key words: enzyme- assisted vacuum distillation, essential oil, citrus leaves, antimicrobial activities, antioxidant activities.