Identification and RP-HPLC-ESI-MS/MS Quantitation of Bitter-Tasting β-Acid Transformation Products in Beer
| Autor: | Daniel Intelmann, Gesa Haseleu, Thomas Hofmann |
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| Rok vydání: | 2009 |
| Předmět: |
Adult
Male Chemical structure Electrospray ionization Mass spectrometry High-performance liquid chromatography Hop (networking) Young Adult Tandem Mass Spectrometry Humans Humulus Chromatography High Pressure Liquid Chromatography Reverse-Phase Chromatography Molecular Structure Chemistry Beer Stereoisomerism General Chemistry Taste Female Epimer General Agricultural and Biological Sciences Acids Quantitative analysis (chemistry) Two-dimensional nuclear magnetic resonance spectroscopy |
| Zdroj: | Journal of Agricultural and Food Chemistry. 57:7480-7489 |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf901759y |
| Popis: | Thermal treatment of the hop beta-acid colupulone under wort boiling conditions, followed by LC-TOF-MS and 1D/2D NMR spectroscopy, revealed cohulupone, hulupinic acid, nortricyclocolupone, two tricyclocolupone epimers, two dehydrotricyclocolupone epimers, two hydroxytricyclocolupone epimers, and two hydroperoxytricyclocolupone epimers as the major bitter-tasting beta-acid transformation products. Among these compounds, the chemical structures of the hydroxy- as well as the hydroperoxytricyclocolupone epimers have not previously been confirmed by 1D/2D NMR experiments. Depending on their chemical structure, these compounds showed rather low recognition thresholds ranging from 7.9 to 90.3 micromol/L. The lowest thresholds of 7.9 and 14.7 micromol/L were found for cohulupone, imparting a short-lasting, iso-alpha-acid-like bitter impression, and for hydroxytricyclocolupone, exhibiting a long-lasting, lingering, and harsh bitterness perceived on the posterior tongue and throat. Furthermore, HPLC-ESI-MS/MS analysis allowed for the first time a simultaneous detection and quantitation of these bitter-tasting beta-acid transformation products in a range of commercial beer samples without any sample cleanup. Depending on the type of beer, these studies revealed remarkable differences in the concentrations of the individual beta-acid transformation products. |
| Databáze: | OpenAIRE |
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