Composition of Egyptian Nerolì Oil

Abstract

The bitter orange flower oil (or nerolì) is an essential product, largely used in perfumery. Nerolì is obtained by hydrodistillation or steam distillation, from the flowers of bitter orange ( Citrus aurantium L.). Since a long time nerolì production is limited and its cost on the market is considerably high. The annual production in Tunisia and Morocco is ca. 1500 Kg, representing more than 90% of the worldwide production. A small amount of nerolì is also produced in Egypt, Spain and Comorros (not exceeding 150 kg totally). Due to the high cost, the producers and the users have tried to obtain less expensive products, with odor characters close to that of nerolì oil to be used as substitute and sometimes as adulterants of the genuine oil. In this study are investigated five samples of Egyptian nerolì oils produced in 2008 and 2009, in the same industrial plant, declared genuine by the producer. For all the samples the composition was determined by GC/FID and by GC/MS-LRI; the samples were also analyzed by esGC to determine the enantiomeric distribution of twelve volatiles and by GC-C-IRMS for the determination of the δ 13CVPDB values of some mono and sesquiterpene hydrocarbons, alcohols and esters. The analytical procedures allowed to quantitatively determining 86 components. In particular the variation of the composition seems to be dependent on the period of production. In fact, the amount of linalool decreases from March to April while linalyl acetate presents an opposite trend, increasing in the same period. The RSD determined for the δ 13CVPDB are very small (max. 3.89%), ensuring the authenticity of all samples. The results are also discussed in function of the limits provided by the European Pharmacopoeia (EP) (2004), AFNOR (1995) and ISO (2002) regulations for genuine nerolì oils.

Analysis of Citrus essential oils: state of the art and future perspectives. A review.

“…GC‐IRMS analyses has also been recently applied to neroli oil: Bonaccorsi et al . defined an authenticity range for genuine Egyptian oils, measuring δ 13 C values for 12 constituents …”

Gas Chromatography‐Combustion‐Isotope Ratio Mass Spectrometry for Traceability and Authenticity in Foods and Beverages

“…Bergamot (Dugo and others ; Mosandl and Juchelka ; Schipilliti and others ), neroli (Bonaccorsi and others ), and lime oils (Bonaccorsi and others ) are further examples of citrus oils with which fraud by blending occurs. To assess these oils for authenticity, several techniques have been employed such as MDGC, GC‐FID, GC/MS, Es‐GC, HPLC, and GC‐C‐IRMS.…”

Gas chromatography combined with mass spectrometry, flame ionization detection and elemental analyzer/isotope ratio mass spectrometry for characterizing and detecting the authenticity of commercial essential oils of Rosa damascena Mill.

“…This relationship is particularly true for structurally related compounds, such as geraniol and geranyl acetate, nerol and neryl acetate or linalool and linalyl acetate. It is evident that the three above‐mentioned esters have δ 13 C values (around 1‰) that are similar to or slightly lower than those of the corresponding alcohols in the essential oil …”

“…in the case of metabolic branching . Intermolecular isotopic correlations have been shown in several authentic essential oils, thus becoming indicative of the authenticity of natural flavors . This relationship is particularly true for structurally related compounds, such as geraniol and geranyl acetate, nerol and neryl acetate or linalool and linalyl acetate.…”