Uruguayan essential oils. Part VI. Composition of lemon oil

Abstract

The composition of 31 genuine Uruguayan lemon oils obtained by industrial processing (FMC on line) during the 1995 season is reported. The samples were representative of all production areas situated in the North and South of Uruguay. The volatile fraction was analysed by HRGC±FID and GC±MS; the enantiomeric distribution of b-pinene, sabinene, limonene, linalol, terpinen-4-ol and a-terpineol was studied by multidimensional HRGC± HRGC; coumarins and psoralens present in the non-volatile residue were analysed by normal phase HPLC. INTRODUCTIONIn recent years, Uruguayan production of lemon oil has been increasing and at the same time the extraction technology has been improved. The composition of the volatile fraction of lemon oil has been widely studied, 2±9 but so far little has been reported about the enantiomeric distribution of its components 10±12 or about the heterocyclic oxygenated compounds present in the non-volatile residue. 13±15In previous papers we analysed the composition of the volatile fraction of Uruguayan lemon oils, both laboratory prepared and industrially produced during the 1989, 1992 and 1993 seasons. 16±18Here we report the results relative to Uruguayan lemon oils industrially produced during the 1995 season. We wished to con®rm the data previously obtained; to detect possible dierences in the oil composition due to the extraction technology or to the production period; to identify new components in the volatile fraction; to analyse the enantiomeric distribution of some components present in the volatile fraction and to study coumarins and psoralens present in the non-volatile residue. Volatile fraction results were compared with those relative to Italian FMC oils. 19±20 EXPERIMENTALThe research was carried out on 31 industrial FMC lemon oils produced in 1995. The oils were divided into north (9 samples) and south (22 samples) oils according to the production area. GC AnalysisVolatile fraction was analysed by HRGC± FID as described: gas chromatograph Fisons Mega Series 5160 equipped with a Shimadzu data processor C-R3A; fused silica column SE-52, 30 m  0X32 mm i.d., ®lm thickness 0.40± 0.45 mm; column temperature, 458C (6 min) to 1808C at 38C/min; injector and detector temperatures, 2808C; carrier gas He 95 kPa; injection mode, split; injected volume, 1 ml of neat oil. ); column temperature 458C (6 min) to 1118C at 38C/min, then to 1608C at 28C/min and at 38/min to 3008C and held for 15 min; carrier gas He was delivered at constant pressure of 70 kPa (40.5 cm/sec). 1 ml of solution (0.33% v/v essential oil/pentane) were injected on a cold on-column system ®tted with an automated actuator. The MS scan conditions were: source temperature, 2008C; interface temperature, 2608C; E energy, 70 eV; mass scan range, 39.00±350.00 amu. Chiral AnalysisEnantiomeric ratios of some monoterpene hydrocarbons (b-pinene, sabinene, limonene) and of some monoterpene alcohols (linalol, terpinen-4-ol, a-terpineol) were obtained by multidimensional gas chromatography, using a developmental model GC±GC 23 set up w...

Composition and Seasonal Variation of the Essential Oils from Two Mandarin Cultivars of Southern Brazil

“…The reported data are averages of two extractions for each type of oil extraction. The average yields for mandarin oils obtained by steam distillation and cold pressing were 0.45 (28). c For quantitative evaluation, all GC peak areas were compared relative to the internal standard (n-tetradecane).…”

“…was supplied by International Flavors & Fragrances (New York). B, identities tentatively assigned by comparing mass spectra with those obtained from the following literature: Adams, R. (28). c For quantitative evaluation, all GC peak areas were compared relative to the internal standard (n-tetradecane).…”

Identification, Synthesis, and Characterization of Novel Sulfur-Containing Volatile Compounds from the In-Depth Analysis of Lisbon Lemon Peels (Citrus limon L. Burm. f. cv. Lisbon)

“…The mixture was transferred to a separatory funnel and washed with a 10% solution of NH 4 Cl (100 mL), a 5% solution of NaHCO 3 (100 mL), and brine (100 mL) and then dried over MgSO 4 . After filtration and concentration, 281 (3.4 g, 70%) was obtained by column chromatography (silica; ethyl acetate/ hexanes): 1 H NMR (CDCl 3 , 400 MHz) δ 4.17−4.29 (m, 2H), 2.88− 3.01 (m, 2H), 1.98−2.12 (m, 4H), 2.05 (s, 3H), 1.73−1.89 (m, 2H), 1.42 (s, 3H); EI-MS 188 (17, M + ), 101 (100), 43 (27), 113 (25), 67 (12), 81 (9), 59 (9), 41 (7), 102 (7), 79 (6), 100 (6).…”

Comparison of Volatile Concentrations in Hand-Squeezed Juices of Four Different Lemon Varieties

“…The composition of lemon peel oil has been the subject of numerous studies reviewed by Lawrence (1-3), although most of these studies concerned commercial oils for which neither the species nor the varieties were specified. A few other studies were carried out on specified varieties (4,5), and a recent study reports on the volatile composition of nine species of lemons (6). Conversely, although lemon juices are the main commercial products of lemons, only few studies (7,8) have been carried out on the lemon juices volatile fraction.…”