Document Detail


On the autoxidation of bitter-tasting iso-alpha-acids in beer.
MedLine Citation:
PMID:  20222658     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The iso-alpha-acids, the major contributor to bitter beer taste, is well-known to strongly degrade during beer aging. The storage of beer in brown glass bottles revealed a strong depletion of the trans-configured isomers in a highly specific manner, whereas the corresponding cis-iso-alpha-acids seemed to be hardly affected. In comparison, storage of beer in polyethylene terephthalate bottles, which are known to be permeable to oxygen, induced a drastic degradation of both isomers independent of their cis/trans configuration. To investigate the chemical transformation of iso-alpha-acids under oxidative storage conditions, suitable model experiments were performed, and the reaction products that formed were identified as previously not reported hydroperoxy- and hydroxyl-allo-iso-alpha-acids by means of one-/two-dimensional NMR and liquid chromatography-mass spectrometry experiments; for example, cis- and trans-configured hydroperoxy-alloisohumulone as well as the corresponding hydroxy-alloisohumulones were generated upon oxidation of cis- and trans-isohumulone independent of their cis/trans configuration. In addition, the oxidation products formed from the various iso-alpha-acid congeners were quantitatively determined in a series of beer samples stored under defined conditions. For the first time, these data help to understand the molecular mechanism involved in the autoxidative degradation of iso-alpha-acids in beer.
Authors:
Daniel Intelmann; Thomas Hofmann
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  58     ISSN:  1520-5118     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-21     Completed Date:  2010-07-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5059-67     Citation Subset:  IM    
Affiliation:
Food Chemistry and Molecular Sensory Science, Technische Universitat Munchen, Freising, Germany.
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MeSH Terms
Descriptor/Qualifier:
Acids / chemistry*
Beer / analysis*
Chromatography, Liquid
Magnetic Resonance Spectroscopy
Mass Spectrometry
Oxidation-Reduction
Chemical
Reg. No./Substance:
0/Acids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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