Analytical, Nutritional and Clinical MethodsHS-SPME coupled to GC/MS for quality control of Juniperus communis L. berries used for gin aromatization
Introduction
Common juniper, Juniperus communis L. (Cupressaceae) is an aromatic and evergreen shrub, whose berries are known for their physiological properties (Barjaktarović et al., 2005, Kallio and Jünger-Mannermaa, 1989). Juniper berries are widely used in flavours, perfumes and pharmaceuticals and to aromatise alcoholic beverages. In particular, they are used with other botanical ingredients in the production of commonly consumed juniper-based spirits, such as gin (Aylott, 2003). According to European regulations (EEC 1576/89), the main flavour in the most common and popular type of gin (London dry gin), which belongs to the “Distilled gin” class, should come from juniper berries. In fact, the “juniper” note was reported as the sensory characteristic distinguishing gins from other alcoholic beverages (McDonnell, Hulin-Bertaud, Sheehan, & Delahunty, 2001). Therefore, the main impact on the perception of dry gin flavour should be related to the presence of several aromatic volatile and semivolatile compounds derived from juniper berries. For this reason, the assessment of the volatile and semivolatile composition of this raw material is of great importance to assure the gin’s final sensory quality. The composition of juniper essential oil may be influenced by several factors, such as the growth site, the plant age, the bushes form and the berries ripeness (Angioni et al., 2003, Kallio and Jünger-Mannermaa, 1989).
Several analytical methods are available for analysing essential oil components from plant materials. Distillation methods such as steam distillation (SD), distillation-solvent extraction (SDE), microwave-assisted extraction (MAE) and supercritical fluid extraction (SFE) have traditionally been applied in this analysis. SDE appears to be the most favourable method for recovering mono- and sesquiterpenes and their oxygenated analogues. Heavier components (diterpenoids and phytosterols) have only been observed in MAE and SFE extracts (Marriott, Shellie, & Cornwell, 2001). One of the disadvantages of the distillation method is that the essential oils may undergo chemical alterations. In addition, heat-sensitive compounds can easily be destroyed. Solvent extraction may cause loss of volatiles during the vacuum evaporation of the solvent (Pourmortazevi, Baghaee, & Mirhosseini, 2004). Moreover, these techniques are time consuming. SFE avoids these problems, but it is expensive on a laboratory scale. Headspace techniques are readily applicable to qualitative analysis. They can be used for comparison and quality control purposes or for the investigation of possible adulteration. These techniques provide information on the compounds in the vapour phase, which are mainly responsible for the odour of the product (Coleman & Lawrence, 1997).
The qualitative and quantitative composition of juniper berries’ essential oil has been subject to several investigations (Angioni et al., 2003, Barjaktarović et al., 2005, Chatzopoulou et al., 2002, Chatzopoulou and Katsiotis, 1995, Gonny et al., 2006, Kallio and Jünger-Mannermaa, 1989, Marongiu et al., 2006, Ochocka et al., 1997, Shahmir et al., 2003). However, few studies have been carried out on the headspace volatiles of juniper berries. At the best of our knowledge, only the static headspace technique has been applied for the analysis of volatile constituents of J. communis cones. Twenty terpenic compounds were detected in this analysis (Chatzopoulou & Katsiotis, 2006). Among headspace techniques, solid phase microextraction (SPME) is a rapid, simple, inexpensive and solvent free technique for the extraction and preconcentration of volatile compounds. It is carried out by a fused silica fibre that is coated with different stationary phases and characterized by its high sensitivity to volatile organic compounds (Yang & Peppard, 1994). In recent years, this technique has been proposed for evaluating the aromatic quality control of several foods (Kataoka et al., 2000, Plutowska and Wardencki, 2007). SPME’s applications have been described in the analysis of the volatile compounds of several plant species (Bicchi et al., 2000, Pawliszyn, 1999). However, to date no literature is available on its application to the analysis of juniper berries.
In the present study, the suitability of SPME coupled to gas chromatography/mass spectrometry (GC/MS) was evaluated as a simple and inexpensive method for undertaking the volatile composition analysis of J. communis berries used for dry gin aromatization.
Section snippets
Reagents and plant material
Standard compounds β-myrcene, (S)-(−)-limonene, linalool, (−)-α-pinene, (−)-β-pinene, γ-terpinene, p-cymene, bornyl acetate, (−)-α-terpineol, (+)-terpinen-4-ol, (−)-β-citronellol, t-β-farnesene, nonanal benzaldehyde and manool (4aR-trans-5-(1,5,5,8aS-tetramethyl-2-methylenedecahydro-1-naphthalenyl)-3-R-methyl-1-penten-3-ol) were purchased from Fluka-Sigma-Aldrich (St. Louis, Missouri, USA) and Fluka. Caryophyllene oxide, β-elemol and β-eudesmol were from M.C.M. Klosterfrau (Köln, Germany). The
Results and discussion
The headspace of J. communis berries intended for dry gin aromatization was analysed by applying the analytical method previously developed for the analysis of gin headspace (Vichi, Riu-Aumatell, Mora-Pons, Buxaderas, & Lopez-Tamames, 2005). The SPME extraction conditions were chosen in order to favour the determination of the less volatile terpenic compounds in addition to the more volatile terpenoids. Besides the more volatile monoterpenoids, which appeared as major compounds (Table 1), the
Acknowledgements
This study was supported by the Generalitat de Catalunya, project 2005SGR00156; by the Ministerio de Ciencia y Tecnología (MCYT), project AGL2005-03451/ALI; and by the Secretaría de Estado de Educación y Universidades (Ministerio de Educación y Ciencia), Ref. SB2003-0118.
References (26)
- et al.
Influence of fibre coating in headspace solid-phase microextraction–gas chromatographic analysis of aromatic and medicinal plants
Journal of Chromatography A
(2000) - et al.
Procedures influencing the yield and the quality of the essential oil from Juniperus communis L. berries
Pharmaceutica Acta Helvetiae
(1995) - et al.
Applications of solid-phase microextraction in food analysis
Journal of Chromatography A
(2000) - et al.
Gas chromatographic technologies for the analysis of essential oils
Journal of Chromatography A
(2001) - et al.
Aromagrams – Aromatic profiles in the appreciation of food quality
Food Chemistry
(2007) - et al.
Chemical composition of the essential oils of Juniperus from ripe and unripe berries and leaves and their antimicrobial activity
Journal of Agricultural and Food Chemistry
(2003) Vodka, Gin and other flavoured spirits
- et al.
Chemical composition of Juniperus communis L. fruits supercritical CO2 extracts: Dependence on pressure and extraction time
Journal of Agricultural and Food Chemistry
(2005) - et al.
Investigation on the supercritical CO(2) extraction of the volatile constituents from Juniperus communis obtained under different treatments of the “berries” (cones)
Planta Medica
(2002) - et al.
Headspace analysis of the volatile constituents from Juniperus communis L. ‘berries’ (cones) grown wild in Greece
Flavour and Fragrance Journal
(2006)