Determination of short chain fatty acids isomers, the sensory active products of hops aging, in beer.

Determination of short chain fatty acids isomers, the sensory active products of hops aging, in beer.

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Important products of hop aging are the C4 and C5 isomers of short chain fatty acids; namely 2-methyl propionic acid (isobutyric acid), 2-methyl butyric acid and 3-methyl butyric acid (isovaleric acid).These acids are sensory active and moreover, after the esterification during beer production they can provide further sensory active compounds contributing to a stale aftertaste.In the framework of this study a sufficiently sensitive and selective method for the determination of these substances in beer was developed.

This method is based on the isolation of the short chain fatty acids and their isomers by means of solid phase extraction (SPE) and followed by quantification using gas chromatography-mass spectrometry (GC-MS).The use of mass spectrometry for the detection eliminated the problem of virginia mill works tobacco road acacia the difficult chromatographic separation and quantification of these compounds.When compared with the usual detection using a flame ionisation detector (FID) the results of the quantitative determination by means of MS are more accurate.

The newly developed and optimized method was used for monitoring changes in the contents of the short chain fatty acids and their isomers in beer produced with both fresh and older hops and by using infusion or decoction brewing methods.Important products of hop aging are the C4 and C5 isomers of short chain fatty acids; namely 2-methyl propionic acid (isobutyric acid), 2-methyl butyric acid and 3-methyl butyric acid (isovaleric acid).These acids are sensory active and moreover, after the esterification during beer production they can provide further sensory active compounds contributing to a stale aftertaste.

In the framework of this study a sufficiently sensitive and selective method for the determination of these substances in beer was developed.This method is based on the isolation of the short chain fatty acids and their isomers by means of solid phase extraction (SPE) and hacklinkci.com followed by quantification using gas chromatography-mass spectrometry (GC-MS).The use of mass spectrometry for the detection eliminated the problem of the difficult chromatographic separation and quantification of these compounds.

When compared with the usual detection using a flame ionisation detector (FID) the results of the quantitative determination by means of MS are more accurate.The newly developed and optimized method was used for monitoring changes in the contents of the short chain fatty acids and their isomers in beer produced with both fresh and older hops and by using infusion or decoction brewing methods.