Analyses of orange spirit flavour by direct-injection gas chromatography-mass spectrometry and headspace solid-phase microextraction/GC-MC

Differentiation of raw spirits of rye, corn and potato using chromatographic profiles of volatile compounds

BACKGROUND

The origin of the raw spirits influences the sensory quality of rectified spirits that are subsequently used for the production of vodka. The aim of this research was to evaluate the effectiveness of two methods based on the comparison of profiles of volatile compounds [solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and gas chromatography with flame ionisation detection (GC-FID)] for the determination of origin of raw spirits obtained from rye, corn (maize) and potato.

RESULTS

Profiles obtained for the volatile compounds by using these methods were different and were influenced by the sample introduction method. The main groups of volatiles obtained using SPME-GC-MS method were fatty acid ethyl esters, while in the case of GC-FID fusel alcohols and ethyl acetate dominated. Data obtained from these methods were treated using principal component analysis and linear discriminant analysis to test the possibility of sample differentiation and classification. It was relatively easy to differentiate potato spirits from the remainder; however, it was not possible to fully distinguish the corn samples from rye samples. The classification ability of the SPME-GC-MS method was 95% but the prediction ability was 97.4%. For the GC-FID method the classification ability was 90.1%, whereas the prediction ability was 94.27%.

CONCLUSIONS

The methods presented can be used for reliable differentiation of potato spirits from corn and rye spirits.

Characterization of the most odor-active volatiles of orange wine made from a Turkish cv. Kozan (Citrus sinensis L. Osbeck)

The aroma-active compounds of cv. Turkish Kozan orange wine were analyzed by sensory and instrumental analyses. Liquid-liquid extraction with dichloromethane was used for extraction of volatile components. According to sensory analysis, the aromatic extract obtained by liquid-liquid extraction was representative of orange wine odor. A total of 63 compounds were identified and quantified in orange wine. The results of the gas chromatography-olfactometry analysis showed that 35 odorous compounds were detected by the panelists. Of these, 28 aroma-active compounds were identified. Alcohols followed by terpenes and esters were the most abundant aroma-active compounds of the orange wine. Among these compounds, ethyl butanoate (fruity sweet), 3-methyl-1-pentanol (roasty), linalool (floral citrusy), gamma-butyrolactone (cheesy burnt sugar), 3-(methylthio)-propanol (boiled potato, rubber), geraniol (floral citrusy), and 2-phenylethanol (floral rose) were the most important contributors to the aroma of the orange wine because they were perceived by all eight panelists.

Determination of terpenes in tequila by solid phase microextraction-gas chromatography-mass spectrometry

Solid phase microextraction and capillary gas chromatography-mass spectrometry were used for the determination of seven terpenes in tequila. The method was selected based on the following parameters: coating selection (PA, PDMS, CW/DVB, and PDMS/DVB), extraction temperature, addition of salt, and extraction time profile. The extraction conditions were: PDMS/DVB fiber, Headspace, 100% NaCl, 25 degrees C extraction temperature, 30 min extraction time and stirring at 1200 rpm. The calibration curves (50-1000 ng/ml) for the terpenes followed linear relationships with correlation coefficients (r) greater than 0.99, except for trans,trans-farnesol (r = 0.98). RSD values were smaller than 10% confirmed that the technique was precise. Samples from 18 different trade brands of "Aged" tequila analyzed with the developed method showed the same terpenes in different concentrations. The analytical procedure used is selective, robust (more than 100 analyses with the same fiber), fast and of low-cost.

Determination of flavour and off-flavour compounds in orange juice by on-line coupling of a pervaporation unit to gas chromatography–mass spectrometry

A method for the analysis of several volatiles compounds responsible for orange juice flavour (ethyl butanoate, limonene, linalool, alpha-pinene, geranial, neral and alpha-terpineol) has been developed. The isolation of this compounds was carried out by pervaporation (PV) followed by on-line gas chromatography-mass spectrometry (GC-MS). The coupling PV-GC-MS has been successfully applied to fresh hand-squeezed orange juices and frozen concentrated ones in order to establish differences in their flavour profile. Method has been validated with recovery spike experiments which showed its applicability for a wide range of concentrations.