Kvasny Prum. 2005; 51(11-12): 374-377 | DOI: 10.18832/kp2005017

Determination of the Fatty Acids in Beer by SPME.Peer-reviewed article

Tomáš HORÁK, Jiří ČULÍK, Marie JURKOVÁ, Pavel ČEJKA, Vladimír KELLNER

Výzkumný ústav pivovarský a sladařský, a. s., Pivovarský ústav Praha

An escalated content of fatty acids during fermentation can influence the quality of final beer. So it is necessary to use the suitable analytical method for the determination of their concentrations in beer or hopped wort. This work presents the simple and rapid possibility of the selective determination of the free fatty acids (C6-C12) in beer or wort by Solid Phase Microextraction (SPME) and gas chromatography. The free fatty acids C6-C12 were extracted by SPME fiber placed in the headspace of vial containing the sample of beer with the addition of salt. Analytes were thermally desorbed from the coated fiber of the SPME in the hot injector of the GC equipped with a fused silica capillary column SPB-1000 and a flame ionisation detector. For the quantitation of these medium-chain fatty acids heptanoic acid and undecanoic acid were used as internal standards. Validated parameters of the optimalized method for the determination of medium-chain fatty acids from beer are shown in this work. This method is time saving, low cost, does not require solvents and provides high sensitivity and reproducibility. It can be recommended for routine control analyses in brewery laboratories.An escalated content of fatty acids during fermentation can influence the quality of final beer. So it is necessary to use the suitable analytical method for the determination of their concentrations in beer or hopped wort. This work presents the simple and rapid possibility of the selective determination of the free fatty acids (C6-C12) in beer or wort by Solid Phase Microextraction (SPME) and gas chromatography. The free fatty acids C6-C12 were extracted by SPME fiber placed in the headspace of vial containing the sample of beer with the addition of salt. Analytes were thermally desorbed from the coated fiber of the SPME in the hot injector of the GC equipped with a fused silica capillary column SPB-1000 and a flame ionisation detector. For the quantitation of these medium-chain fatty acids heptanoic acid and undecanoic acid were used as internal standards. Validated parameters of the optimalized method for the determination of medium-chain fatty acids from beer are shown in this work. This method is time saving, low cost, does not require solvents and provides high sensitivity and reproducibility. It can be recommended for routine control analyses in brewery laboratories.

Keywords: fatty acids, SPME, beer, gas chromatography

Published: November 1, 2005