Effects of hot water treatment on the essential oils of calamondin

Volatile constituents of calamondin peel or whole fruit were obtained by cold pressing, steam distillation, or hot water treatment at 90°C for 15 minutes followed by steam distillation. The volatile components of the essential oils were identified by direct injection coupled with gas chromatography–flame ionization detector. A total of 54 compounds were identified, including 13 monoterpenes, 7 monoterpene alcohols, 1 monoterpene oxide, 4 monoterpene aldehydes, 2 monoterpene ketones, 4 monoterpene esters, 12 sesquiterpenes, 3 aliphatic alcohols, 6 aliphatic aldehydes, and 2 aliphatic esters, with limonene and β-myrcene as the major compounds. The results showed that hot water treatment increased the yields of essential oils from both peel and whole fruit. The relative percentage of the principle constituents in the various prepared essential oils were similar, except for some minor compounds, including linalool, terpinen-4-ol, α-terpineol, and carvone, the content of which were boosted by steam distillation. Whole fruit contained higher levels of monoterpene alcohols than peel did.