Headspace solid‐phase microextraction analysis of volatile compounds from spice essential oils in dry flavourings

The composition of volatile compounds in nine spices was analysed by means of headspace solid‐phase microextraction (HS‐SPME) from dry flavourings of the spice essential oils, to devise an effective method to determine the content of the essential oils. The HS‐SPME was combined with GC‐MS and GC‐FID for identification and quantification of the volatile compounds. The optimisation of the extraction conditions was carried out by response surface methodology. The evaluation of the analytical parameters indicated that the method had a high precision (coefficient of variations lower than 3%), it was linear (response factors were smaller than 5%) and recoveries were higher than 89%. In the ruggedness test, sample quantity and pre‐extraction time were the factors that stood out as the causing of the greater effects on the analytical results.     

Determination of volatile compounds to characterize fish spoilage using headspace/mass spectrometry and solid‐phase microextraction/gas chromatography/mass spectrometry

Changes in volatile compounds were monitored in whiting (Merlangius merlangus), cod (Gadus morhua) and mackerel (Scomber scombrus) and related to spoilage. Data are presented from headspace/mass spectrometric (HS/MS) analysis and solid‐phase microextraction/gas chromatographic/mass spectrometric (SPME/GC/MS) analysis at two time points (day 0 and day 10) during storage at 4 °C. HS/MS revealed 24 ions that could be used as markers of spoilage. SPME/GC/MS identified 86 compounds, 20 of which could perhaps be used to characterize freshness: principally alcohols, ketones, aldehydes and C₂–C₁₁ esters. Compounds common to the three species studied appear to be generated by microbial degradation. Copyright © 2005 Society of Chemical Industry     

Analysis of brandy aroma by solid‐phase microextraction and liquid–liquid extraction

Headspace solid‐phase microextraction (SPME) and continuous liquid–liquid extraction (LLX) with Freon were used to extract and analyse aroma volatiles in brandy. In general, SPME using a non‐polar polydimethylsiloxane coating was more selective for esters and acids than was LLX. LLX using Freon 11 extracted the higher alcohols more efficiently than SPME. Relative differences in volatiles between brandies made from Vitis vinifera L cv Colombard and Vitis vinifera L cv Ugni blanc were observed, particularly for hexanol, 3‐methylbutylacetate, 3‐methylbutanol and 3‐methylbutyloctanoate. In addition, a combination of SPME with GC–olfactometry was used to provide more detailed information on sensory characteristics of varietal brandies. © 2000 Society of Chemical Industry     

Production of volatile compounds by hairy root cultures of Cichorium intybus L under the influence of fungal elicitors and their analysis using solid‐phase micro extraction gas chromatography–mass spectrometry

Hairy root cultures of Cichorium intybus L produced volatile aromatic compounds under the influence of fungal elicitors. It was observed that the intensity of the production of volatile aromatic compounds in the hairy root cultures of C intybus with 10 ml l^?1 media filtrate (MF) of Phytopthora parasitica var nicotiana reached a maximum on the 21st day, as seen by a quantitative flavour profiling method. It was noted that, during the time course, treatment with 10 ml l^?1 MF of P parasitica to the MS basal liquid medium containing hairy root cultures of chicory resulted in changed root morphology with cell wall thickening and shear. The components of the volatile aromatic compounds were identified as a propyl isovalerate, undecanal, nonanol, isoamyl nonanoate and 2‐decene‐1‐ol. The mass spectra of all these compounds matched well with the NIST/EPA/NIH library and by comparing with the Kovats index of volatile compounds. The major fruity note was due to the presence of two of the major volatile components, namely propyl isovalerate and isoamyl nonanoate, which were also produced at higher concentration on day 21. This response of chicory hairy root cultures to the fungal elicitor producing volatile aromatic compounds would imply eco‐physiological functions, possibly for plant defence system. Copyright © 2003 Society of Chemical Industry     

Determination of flavour compounds in beer using stir‐bar sorptive extraction and solid‐phase microextraction

The analysis of volatile compounds in beer is important for quality control in the brewing industry. In this study, stir‐bar sorptive extraction (SBSE) and solid‐phase microextraction (SPME), two solvent‐less enrichment techniques, were applied in combination with gas chromatography flame ionization detection (GC/FID) for the determination of four flavour compounds (isoamyl acetate, ethyl hexanoate, benzaldehyde, myrcene) in beer. Limits of detection, linearity and repeatability of both methods were determined using standard ethanol solutions, while accuracy was determined by conducting recovery tests on commercial beer samples. Both methods were characterized by high linearity (r > 0.996) and repeatability (RSD = 1.76–10.66%). When both methods were compared, higher recoveries were obtained by SBSE, with limits of detection 1.8–2.8 times lower compared with SPME. In the analysis of commercial beer samples using both methods, SBSE analysis resulted in higher recoveries, therefore demonstrating promise for the analysis of beer volatiles. Copyright © 2015 The Institute of Brewing & Distilling