Chemical composition and functional properties of Vietnamese pomelo (Tan Trieu, Doan Hung, Thanh Tra) peel's essential oils extracted by cold pressing and vaccuum hydro- distillation methods

Abstract

Chemical composition, antioxidant and antimicrobial activities of peel essential oils (EOs) from three pomelo varieties Tan Trieu, Thanh Tra, Doan Hung (Citrus grandis Osbeck) extracted by cold pressing and vaccum-hydrodistillation method were investigated. Nine main monoterpenes of EOs were detected by gas chromatography. Chemical composition of cold pressed EOs expressed better than vaccum-hydrodistilation EOs. DPPH assay and dilution method were employed to test antioxidant and antibacterial activity. All cold pressed EOs showed stronger effect on radical scavenging and to bacterial strains (B. cereus and S. typhi). Among cold pressed EOs, Tan Trieu peel EO gave the best radical scavenging activity, followed with Thanh Tra and Doan Hung EOs. Lower effects were from Tan Trieu, Thanh Tra, Doan Hung vacuum-hydrodistillated EOs. The influents of pomelo peel EOs on S. typhi were not as good as B. cereus. Doan Hung and Thanh Tra EOs offered nearly the same antibacterial activity. Tan Trieu EOs had weakest impact. Results of antioxidant and antimicrobial assays indicated that all tested EOs had their own effects. Both the antioxidant and antimicrobial activities of oils varied as result of various cultivars and extraction methods leading to differences in chemical compositions.

Keywords: pomelo Essential oil Gas chromatography Chemical composition Antioxidant activity Antibacterial activity