Comparison of two extraction methods for evaluation of volatile constituents patterns in commercial whiskeysElucidation of the main odour-active compounds

Abstract

An analytical procedure based on manual dynamic headspace solid-phase microextraction (HS-SPME) method and the conventional extraction method by liquid-liquid extraction (LLE), were compared for their effectiveness in the extraction and quantification of volatile compounds from commercial whiskey samples. Seven extraction solvents covering a wide range of polarities and two SPME fibres coatings, has been evaluated. The highest amounts extracted, were achieved using dichloromethane (CH 2 Cl 2 ) by LLE method (LLE CH 2 Cl 2 ) and using a CAR/PDMS fibre (SPME CAR/PDMS ) in HS-SPME. Each method was used to determine the responses of 25 analytes from whiskeys and calibration standards, in order to provide sensitivity comparisons between the two methods. Calibration curves were established in a synthetic whiskey and linear correlation coefficient (r) were greater than 0.9929 for LLE CH 2 Cl 2 and 0.9935 for SPME CAR/PDMS , for all target compounds. Recoveries greater than 80% were achieved. For most compounds, precision (expressed by relative standard deviation, R.S.D.) are very good, with R.S.D. values lower than 14.78% for HS-SPME method and than 19.42% for LLE method. The detection limits ranged from 0.13 to 19.03 g L −1 for SPME procedure and from 0.50 to 12.48 g L −1 for LLE.A tentative study to estimate the contribution of a specific compound to the aroma of a whiskey, on the basis of their odour activity values (OAV) was made. Ethyl octanoate followed by isoamyl acetate and isobutyl alcohol, were found the most potent odour-active compounds.

Comparative analysis of the volatile fraction from Annona cherimola Mill. cultivars by solid-phase microextraction and gas chromatography–quadrupole mass spectrometry detection

“…The analysis of headspace volatile compounds by HS-SPME is greatly influenced by the vapour pressure of flavour compounds of the matrix. Since the first HS-SPME fibres became commercially available, they have been used in several applications, including a wide range of food analysis, like volatile composition in wines [14][15][16], beers [17,18], whiskeys [19,20], honeys [21], medicinal plants [22,23] and several kinds of fruits [24,25]. Up to now, this technique has been widely applied in the several matrixes.…”

Volatile Compounds of Raw Spirits from Different Distilling Stages of Luzhou-flavor Spirit

“…In some previous literatures, numerous sample preparation methods, such as LLE, solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE), coupled with GC-MS were used to determine volatile compounds in Chinese spirits and wines (Hernandez-Gomez et al;, Sanchez-Palomo et al, 2009Fan and Qian, 2006a). LLE represented a better applicability for sample preparation in previous experiments because all volatile compounds (low, medium and high volatility) can be analyzed in one or more extraction steps (Hernanz et al, 2008;Caldeira et al, 2007). Prior to GC-MS detection, the main volatile compounds determined in previous literature (Fan and Qian, 2006a) were used to validate the accuracy of the detection method in the present research.…”

Volatile composition of tequila. Evaluation of three extraction methods Composición volátil del tequila. Evaluación de tres métodos extractivos

“…The election of an extractive method to separate these compounds has a *Corresponding author. Email: smartinde@itesm.mx { special importance since the profile of compounds obtained is directly correlated with the extractive method used (Bosch-Fuste et al, 2007;Caldeira, Rodrigues, Perestrelo, Marques, & Camara, 2007).…”

“…There is a considerable amount of extractive methods that have been used for the characterization of the volatile fraction of alcoholic drinks, such as liquid-liquid in batch (Benn & Peppard, 1996;Pino, Villarreal, & Roncal, 1994;Sefton, Francis, & Williams, 1993) or continuous (Gonzalez-Vinas, PerezCoello, Salvador, Cabezudo, & Martin-Alvarez, 1996;Pino et al, 1994), adsorption-desorption (Girard, Kopp, Reynolds, & Cliff, 1997), headspace (Stashenko, Macku, & Shibamoto, 1992), microwave (Razungles et al, 1994), simultaneous distillation-extraction (Blanch, Reglero, & Herraiz, 1996;Blanch, Tabera, Herraiz, & Reglero, 1993;Schultz, Flath, Mon, Eggling, & Teranishi, 1977) and solid phase microextraction (SPME) (Caldeira et al, 2007; De LeonRodriguez, Gonzalez-Hernandez, De la Rosa, Escalante-Minakata, & Lopez, 2006;Pen˜a-Alvarez, Capella, Juarez, & Labastida, 2006). According to the method, several operational conditions are used, such as the solvent or fiber type, as well as the sample's volume, and extraction time, etc.…”

“…However, even though there are a wide variety of methods, the profile of volatile compounds obtained from each method is different since it depends not only just on the type of extraction (Caldeira et al, 2007;Jennings & Filsoof, 1977;Razungles, et al, 1994) but also on the selected solvents (Caldeira et al, 2007) and the extraction time and conditions. Additionally, the concentration method used to concentrate the obtained extract influences the final profile of volatile compounds (Hubert, Brunerie, Le Quere, & Drilleau, 1990;Langlois, Malterre, & Etievant, 1997).…”