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Headspace solid‐phase microextraction combined with mass spectrometry as a powerful analytical tool for profiling the terpenoid metabolomic pattern of hop‐essential oil derived from Saaz variety
Author(s) -
Gonçalves João,
Figueira José,
Rodrigues Fátima,
Câmara José S.
Publication year - 2012
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201200244
Subject(s) - solid phase microextraction , chemistry , chromatography , terpenoid , essential oil , gas chromatography–mass spectrometry , mass spectrometry , gas chromatography , aroma , humulus lupulus , sample preparation , food science , biochemistry , pepper
Hop ( Humulus lupulus L., Cannabaceae family) is prized for its essential oil contents, used in beer production and, more recently, in biological and pharmacological applications. In this work, a method involving headspace solid‐phase microextraction and gas chromatography–mass spectrometry was developed and optimized to establish the terpenoid (monoterpenes and sesquiterpenes) metabolomic pattern of hop‐essential oil derived from Saaz variety as a mean to explore this matrix as a powerful biological source for newer, more selective, biodegradable and naturally produced antimicrobial and antioxidant compounds. Different parameters affecting terpenoid metabolites extraction by headspace solid‐phase microextraction were considered and optimized: type of fiber coatings, extraction temperature, extraction time, ionic strength, and sample agitation. In the optimized method, analytes were extracted for 30 min at 40°C in the sample headspace with a 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane coating fiber. The methodology allowed the identification of a total of 27 terpenoid metabolites, representing 92.5% of the total Saaz hop‐essential oil volatile terpenoid composition. The headspace composition was dominated by monoterpenes (56.1%, 13 compounds), sesquiterpenes (34.9%, 10), oxygenated monoterpenes (1.41%, 3), and hemiterpenes (0.04%, 1) some of which can probably contribute to the hop of Saaz variety aroma. Mass spectrometry analysis revealed that the main metabolites are the monoterpene β‐myrcene (53.0 ± 1.1% of the total volatile fraction), and the cyclic sesquiterpenes, α‐humulene (16.6 ± 0.8%), and β‐caryophyllene (14.7 ± 0.4%), which together represent about 80% of the total volatile fraction from the hop‐essential oil. These findings suggest that this matrix can be explored as a powerful biosource of terpenoid metabolites.