Hop Resins and Beer Flavour Iii. Hop Resins in Beer*

Whitear, A. L.; Hudson, J. R.

doi:10.1002/j.2050-0416.1964.tb01962.x

Cited by 17 publications

(17 citation statements)

References 5 publications

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“…Panelists scaled the overall bitterness intensity of a given sample using a sliding bar scale (0 = none, 20 = extreme), and the scaling data were collected using Qualtrics. After assessing a sample, the panelists were instructed to rinse their mouths with a 0.1% pectin solution to aid in the reduction of bitterness carry-over 35 and then to rinse their mouths again with deionized water. Panelists were instructed to wait until all perceivable bitterness had dissipated before tasting the next sample.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers

Hahn

Lafontaine

Pereira

et al. 2018

J. Agric. Food Chem.

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The range of different nonvolatile constituents extracted from hops in highly hopped beers suggests that isohumulones may not be the sole contributor to beers' bitterness. Among brewers producing hop-forward beer styles, there is concern that the bitterness unit (BU) is no longer an accurate predictor of beer bitterness. This study examined factors within the beer matrix that influence sensory bitterness perception in highly hopped beers. Over 120 commercial beers were evaluated using sensory and instrumental techniques. Chemical analysis consisted of the BU via spectrophotometry, hop acids via high-performance liquid chromatography, total polyphenols via spectrophotometry, and alcohol content plus real extract via an Alcolyzer. Sensory analysis was conducted over two studies, and the beers' overall bitterness intensities were rated using a 0-20 scale. This study identified that the BU measurement predicts sensory bitterness with a nonlinear response, and it proposed an alternative approach to predicting bitterness based on isohumulones, humulinones, and ethanol concentrations. The study also revealed the importance of oxidized hop acids, humulinones, as a significant contributor to beer bitterness intensity.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers

Hahn

Lafontaine

Pereira

et al. 2018

J. Agric. Food Chem.

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show abstract

“…7*5:4*1), we estimate that These are presumably the equilibrium proportions, and are in good agreement with estimates of the proportions of the two isomers made from the countercurrent distribution studies. 19 No significant difference could be detected (by proton resonance spectroscopy) between sam ples prepared on different occasions, and either distilled or not. these hydrogens have been exchanged for deuterium.…”

Section: Discussionmentioning

confidence: 92%

“…In a similar manner, tsohumulone A is resolved into two spots by reversed phase paper chromatography. 19 Thus, there is much evidence for the existence of two isomeric forms of tsohumulone A, although at present the separation of the two isomers on a pre parative scale, so that their properties can be compared, has not been reported. It should perhaps be mentioned, also, that hydrogenation of tsohumulone A leads to a crystalline tetrahydrotsohumulone.2»ls Differ ent preparations, however, show a con siderable variation in m.p., indicating that this compound may also be a slightly varying mixture of two isomers.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…It was later found that two theoretical curves could be fitted under the tsohumulone A countercurrent distribution peak, but several hun dreds of transfers would be necessary to separate the two components. 19 By means of reversed phase chromatography, Spetsig demonstrated that the product of boiling humulone in a buffer solution of pH 5-0 gave rise to two separate peaks,13 whereas the bittering principles of beer gave rise to five or six peaks. 16 It was thus suggested that each analogue of the a acids gave rise to two isomers of the corresponding tso-compound.…”

Section: Introductionmentioning

confidence: 99%

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CHEMISTRY OF HOP CONSTITUENTS: XXII. PROTON MAGNETIC RESONANCE SPECTROSCOPY OFISOHUMULONE A

Burton

Stevens

Elvidge

1964

Journal of the Institute of Brewing

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Knowledge of the structure of isohumulone A is reviewed. Its proton magnetic resonance spectrum has been interpreted with the aid of the spectra of the two isomers of humulinic acid. It is concluded that isohumulone A consists of a mixture of stereoisomers, trans and cis with respect to the 4‐isohexenoyl and 5‐isopentenyl chains, in the ratio of about 60% trans (i.e., with the stereochemistry of humulinic acid B) to 40% cis (i.e., humulinic acid A stereochemistry). Humulone has been isomerized into isohumulone A in deuterium oxide, and unlabelled isohumulone A has been hydrolysed into humulinic acid A using sodium deuteroxide in deuterium oxide. The modified spectra assisted some of the assignments.

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Struktur und Bittere in der Huluponreihe

Gienapp

Schröder

1975

Nahrung

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Uurch Bestimmung von Schwcllcnwcrtkonzcntratioiicn und durch Untcrschiedspriifungcn wircl untersucht, welchen EinfluW die Lange und die Verzweigung der Alkyl-bzw. Alkenyl-und der Acylseitenkctten sowie das Vorhandensein %-on Doppelbindungen in den Seitenkcttcn auf dic Bittere von 5,5-Dialkyl (bnv. Alkenyl-)-~-acylcyclopentan-1,2,~-trionen (Huluponanalogen) haben. Zur Abschatzung des Einflusses der Carbonylgruppe in einer Seitenkettc und des Eiiiflusses der Veratherung und der Reduktion der Enolgruppe des Kerns auf die Bittere werden entsprechende Derivate des ~-Isobutyryl-~-isobutyl-~-(~-methylbut-~-enyl)cyclopentan-~,~, 4-trions hergestellt uiid in Triangelanordnung lctzterem gegeniibergestellt. Durch diesc Untersuchung werden verschiedene Zusaminenhange zwischen der Struktur und der Bittere in dcr Keihe der Huluponanalogen offensichtlich. Eine Verlangerung sowohl der Acyl-als auch der Alkylseitenketten bewirkt eine signifikante Abnahme der Bittcrschwellenwertkonzentrationen. Huluponanaloge niit z kleinen Alkylgruppen (Methyl-odcr Athylgruppen) a m geminal substituierten Kohlenstoffatoin sind nur noch schwach bitter. Die Gegenwart einer olefinischen Doppelbindung wirkt der Erniedrigung des Schwellenwertes durch die Verlangerung dcr Seitenkettc cntgcgcn. Die Substanzen niit gradkettigen Alkyl-bzw. Acylgruppcn sind starker bittcr als ihrc vcrzweigten Isomeren. Ein durch Umsetzung e k e s Huluponanalogen niit Diazornethan hergestellter Enolmethylathcr weist beim Vergleich mit den1 Huluponanalogen keinen signifikanten Unterschied in dcr Stiirkc der Bittere auf. Dagegen bewirkt die Reduktion der endocyclischen Carbonylgruppc des Cyclopentantrionsysteins zur sekundaren Alkoholgruppe einc dcutliche Abnahmc dcr Bittcrc. Das durch Keduktion der Carbonylgruppe in der Acylscitcnkctte gcwonncne , ,Desoxyhuluponanaloge" ist eiiideutig starker bitter als das entsprechende Huluponanaloge.

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Hop Resins and Beer Flavour Iii. Hop Resins in Beer*

Cited by 17 publications

References 5 publications

Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers

Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers

CHEMISTRY OF HOP CONSTITUENTS: XXII. PROTON MAGNETIC RESONANCE SPECTROSCOPY OFISOHUMULONE A

Struktur und Bittere in der Huluponreihe

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