Comparison of lemon oil composition after using different extraction methods

Kibris lemon (Citrus limon (L.) Burm. f.) peel was extracted by supercritical CO2 extraction (SFE), cold pressing (CP) and hydrodistillation (HD) methods. SFE, CP and HD methods have been compared and evaluated for their effectiveness in the separation of extract from fresh lemon peels. The chemical compositions of the three different extract samples were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Forty-four components were fully characterized by mass spectra and linear retention indices. The lemon extracts showed a high content of limonene (71.81%, 70.36% and 72.48%) with gamma-terpinene (8.72%, 8.91% and 8.88%), beta-pinene (6.61%, 6.72% and 6.60%), myrcene (1.55%, 1.59% and 1.73%), sabinene (1.21%, 1.48% and 1.09%), alpha-pinene (0.98%, 1.27% and 0.98%) and p-cimene (0.87%, 1.23% and 0.87%) being the major monoterpene hydrocarbons in the SFE, CP and HD methods, respectively. The principal sesquiterpene hydrocarbon was beta-bisabolene (1.42%, 1.41% and 1.22%) in the SFE, CP and HD extracts, respectively. Neryl acetate and geranial were the main oxygenated compounds (1.25%, 1.28% and 1.21%) and (1.13%, 0.97% and 0.99%), in the SFE, CP and HD extracts, respectively. The composition of lemon extract has been split into six classes (monoterpene hydrocarbons, sesquiterpene hydrocarbons, carbonyl compounds, alcohols, esters and oxides). It was noted that there were significant differences in the carbonyl compounds, alcohol and ester classes in the SFE, CP and HD extracts.