Chemical Composition and Antimicrobial Activity of Pummelo (Citrus maxima) Essential Oil Derived from Fruit Peel

Citrus genus is notable for peel essential oils which are valuable by-products during Citrus processing. In this study, it was aimed to determine chemical composition and antimicrobial activity of the essential oil of pummelo peel (PEO). The essential oil was obtained by hydrodistillation from flavedo layer of the peel. It was subjected to Gas Chromatography/Mass Spectrometry (GC/MS) for identification of its volatiles and a total of sixty-two compounds were identified. Monoterpenes constituted 89.36% of PEO, mostly by D-limonene (76.97%) and beta-myrcene (6.37%). The essential oil became prominent especially with its nootkatone content (1.13%). In antimicrobial activity assays, broth macrodilution method was used against to Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella Enteritidis, Saccharomyces cerevisiae and Candida albicans. According to the test results, minimum inhibitory concentrations of the essential oil ranged between 2000 and 16000 mu g/mL for S. aureus, B. cereus, S. cerevisiae and C. albicans. No inhibitory effect was observed on E. coli and S. Enteritidis although 32000 mu g/mL PEO was applied. On the basis of the results obtained, it was thought that PEO could be used as a natural and inexpensive flavouring and antimicrobial agent by the food and pharmaceutical industries via valorization of pummelo peel.

Automated summary

This study determined the chemical composition and antimicrobial activity of pummelo peel essential oil (PEO). The essential oil was mainly composed of monoterpene compounds, with nootkatone being the most prominent. The antimicrobial activity assays showed that PEO had inhibitory effects on Staphylococcus aureus, Bacillus cereus, Saccharomyces cerevisiae, and Candida albicans, making it a potential natural flavoring and antimicrobial agent for the food and pharmaceutical industries.