New Bitter Substances of Beer: Lupoxes c and Lupdoxes b

Kowaka, Masahiro; Kokubo, Eiichi; Kuroiwa, Yoshiro

doi:10.1080/00960845.1972.12005958

Cited by 8 publications

(3 citation statements)

References 1 publication

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“…Contrary to the well understood re-arrangement of the a-acids into the cis-and trans-iso-a-acids, the information available on bitter compounds generated from the b-acids upon wort boiling is rather scarce. Although some oxidative degradation products of b-acids, such as, e.g., so-called lupoxes, lupdoxes, lupdeps, and lupdols (Kokubo, Kowaka, & Kuroiwa, 1971; Kowaka, Kokubo, & Kuroiwa, 1972, as well as tricyclo-oxycolupulones (Verzele, Van de Velde, & Dewaele, 1983), are reported in literature, the sensory impact of these compounds on beer bitterness is unclear.…”

Section: Introductionmentioning

confidence: 98%

Structure determination and sensory evaluation of novel bitter compounds formed from β-acids of hop (Humulus lupulus L.) upon wort boiling

Haseleu¹,

Intelmann²,

Hofmann³

2009

Food Chemistry

107

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Section: Introductionmentioning

confidence: 98%

Structure determination and sensory evaluation of novel bitter compounds formed from β-acids of hop (Humulus lupulus L.) upon wort boiling

Haseleu¹,

Intelmann²,

Hofmann³

2009

Food Chemistry

107

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“… Upon cleavage of the variable alkanoyl side chain, the various hulupone congeners are further truncated to give hulupinic acid ( 59 , Figure ). Additionally, incubation experiments with hops revealed a series of oxidation products, namely, lupoxes, lupdoxes, lupdeps, lupdols, − and tricyclooxycolupulones . Recently, the formation of tri- and tetracyclic degradation products in beer (Figure ) − indicated the stability of hop-derived compounds in beer to be dependent on the pH value.…”

Section: Introductionmentioning

confidence: 99%

The Bitter Chemodiversity of Hops (Humulus lupulus L.)

Dresel

Vogt

Dunkel

et al. 2016

J. Agric. Food Chem.

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This paper evaluates the influence of genotype on the photosynthetic activity of hops in the period critical for generating yield. Results over three years from measuring the photosynthesis rate statistically show an increase in the photosynthetic activity of hop plants in the flowering stage. The average photosynthetic rates from measurements on the second date (BBA 65) in the years 2007, 2008, and 2009 increased by 17.9%, 45.6%, and 49.2%, respectively. Different photosynthesis curve trends during the final stage of ontogenesis of the plants indicate the maturity level of each hop genotype. As regards the genotypes for which photosynthesis did not reduce significantly, it may be assumed that such plants had not reached technical maturity. The results from the three-year study also show that any promising genotype, with respect to the photosynthesis rate and yield, is the result of breeding of new varieties with greater resistance to drought and high temperatures. Very good results in photosynthetic activity were reached by the new varieties exhibiting high yield and a similar chemical composition to Saaz hop and those sharing the same origins to Saaz, showing a higher content of bitter substances. In 2008 and 2009, all three new forms reached yield levels of 2.35 to 3.12 t/ha of dry hops.

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“…Several previous investigations − ,,− have been reported on the structures of (oxidative and light-induced) degradation of hop-derived bitter acids as well as their underlying formation mechanisms. In particular, the 3-methyl-2-butenyl side chains of α-acids, β-acids, and iso-α-acids and the isohexenoyl side chain of iso-α-acids are very sensitive to oxidation, either at the double bounds or in the allylic positions.…”

Section: Discussionmentioning

confidence: 99%

Metabolism of Hop-Derived Bitter Acids

Cattoor¹,

Dresel

Bock³

et al. 2013

J. Agric. Food Chem.

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In this study, in vitro metabolism of hop-derived bitter acids was investigated. Besides their well-known use as bitter compounds in beer, in several studies, bioactive properties have been related to these types of molecules. However, scientific data on the absorption, distribution, metabolism, and excretion aspects of these compounds are limited. More specific, in this study, α-acids, β-acids, and iso-α-acids were incubated with rabbit microsomes, and fractions were subjected to LC-MS/MS analysis for identification of oxidative biotransformation products. Metabolism of β-acids was mainly characterized by conversion into hulupones and the formation of a series of tricyclic oxygenated products. The most important metabolites of α-acids were identified as humulinones and hulupones. Iso-α-acids were found to be primarly metabolized into cis- and trans-humulinic acids, next to oxidized alloiso-α-acids. Interestingly, the phase I metabolites were highly similar to the oxidative degradation products in beer. These findings show a first insight into the metabolites of hop-derived bitter acids and could have important practical implications in the bioavailability aspects of these compounds, following ingestion of hop-based food products and nutraceuticals.

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New Bitter Substances of Beer: Lupoxes c and Lupdoxes b

Cited by 8 publications

References 1 publication

Structure determination and sensory evaluation of novel bitter compounds formed from β-acids of hop (Humulus lupulus L.) upon wort boiling

Structure determination and sensory evaluation of novel bitter compounds formed from β-acids of hop (Humulus lupulus L.) upon wort boiling

The Bitter Chemodiversity of Hops (Humulus lupulus L.)

Metabolism of Hop-Derived Bitter Acids

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