Composition and Biogenesis of Essential Oil of Hops

Roberts, J. B.; Stevens, Roger

doi:10.1002/j.2050-0416.1962.tb01884.x

Cited by 19 publications

(18 citation statements)

References 29 publications

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“…It has been proposed that geranic acid is a derivative of geraniol and geranial, which are known as hop-derived flavor compounds, especially present in flavor hops. ,− ,, In previous studies, − geranic acid was found in lemongrass, ginger, lemon oil, tomato, and grape, which are raw materials used for wine making. Methyl geranate, which is a methyl ester of geranic acid, has been reported as a compound derived from hop oil. ,,, Roberts et al assumed geranic acid to be a possible precursor of methyl geranate, which they first identified in hop oil . Peacock et al analyzed three commercial beers and detected geranic acid in only one of the beer samples at trace levels (1 μg/L) .…”

Section: Resultsmentioning

confidence: 99%

“…Methyl geranate, which is a methyl ester of geranic acid, has been reported as a compound derived from hop oil. 19,20,35,36 Roberts et al assumed geranic acid to be a possible precursor of methyl geranate, 36 which they first identified in hop oil. 35 Peacock et al analyzed three commercial beers and detected geranic acid in only one of the beer samples at trace levels (1 μg/L).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Identification and Characterization of Geranic Acid as a Unique Flavor Compound of Hops (Humulus lupulus L.) Variety Sorachi Ace

Sanekata

Tanigawa

Takoi

et al. 2018

J. Agric. Food Chem.

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Hops are natural ingredients used to impart bitterness and flavor to beer. Recently, new varieties of hops have attracted global research attention. The Sorachi Ace variety, in particular, interests many craft brewers. This hop imparts characteristic varietal aromas, including woody, pine-like, citrus, dill-like, and lemongrass-like, to finished beers. Here, we investigated specific flavor compounds derived from Sorachi Ace using selectable one-dimensional or two-dimensional gas chromatography−olfactometry/mass spectrometry and head space-solid phase microextraction−gas chromatography−mass spectrometry. The results showed that a unique volatile compound, geranic acid, was present at a significant level only in the test beer brewed with the Sorachi Ace hop. Furthermore, sensory evaluation techniques revealed that geranic acid has very unique characteristics. This compound is not odor-active but functions as an enhancer for hop-derived terpenoids at subthreshold levels.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Identification and Characterization of Geranic Acid as a Unique Flavor Compound of Hops (Humulus lupulus L.) Variety Sorachi Ace

Sanekata

Tanigawa

Takoi

et al. 2018

J. Agric. Food Chem.

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“…from Žatec (Saaz) hops . Unlike β ‐myrcene and α ‐humulene and β ‐caryophyllene; β ‐farnesene is only found in certain hop varieties and usually in low amounts .…”

Section: Hop Essential Oilsmentioning

confidence: 99%

“…Since the boiling point of the non‐volatile fraction is higher than that of α ‐humulene in early hop oil examination, this portion was more challenging to analyse . However, these higher boiling substances are of interest to the brewer since these will most likely be retained in the wort after boiling and they may eventually find their way into the finished beer . The total oxygenated fraction is a complex mixture of alcohols, aldehydes, acids, ketones, epoxides and esters.…”

Section: Hop Essential Oilsmentioning

confidence: 99%

Humulus lupulus- a story that begs to be told. A review

Schönberger²,

et al. 2014

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The hop cones of the female plant of the common hop species Humulus lupulus L. are grown almost exclusively for the brewing industry. Only the cones of the female plants are able to secrete the fine yellow resinous powder (i.e. lupulin glands). It is in these lupulin glands that the main brewing principles of hops, the resins and essential oils, are synthesized and accumulated. Hops are of interest to the brewer since they impart the typical bitter taste and aroma to beer and are responsible for the perceived hop character. In addition to the comfortable bitterness and the refreshing hoppy aroma delivered by hops, the hop acids also contribute to the overall microbial stability of beer. Another benefit of the hop resins is that they help enhance and stabilize beer foam and promote foam lacing. In an attempt to understand these contributions, the very complex nature of the chemical composition of hops is reviewed. First, a general overview of the hop chemistry and nomenclature is presented. Then, the different hop resins found in the lupulin glands of the hop cones are discussed in detail. The major hop bitter acids (α-and β-acids) and the latest findings on the absolute configuration of the cis and trans iso-α-acids are discussed. Special attention is given to the hard resins; the known δ-resin is reviewed and the ε-resin is introduced. Recent data on the bittering potential and the antimicrobial properties of both hard resin fractions are disclosed. Attention is also given to the numerous essential oil constituents as well as their contributions to beer aroma. In addition to the aroma contribution of the well-known essential oil compounds, a number of recently identified sulfur compounds and their impact on beer aroma are reviewed. The hop polyphenols and their potential health benefits are also addressed. Subsequently, the importance of hops in brewing is examined and the contributions of hops to beer quality are explained. Finally, the beer and hop market of the last century, as well as the new trends in brewing, are discussed in detail. Hop research is an ever growing field of central importance to the brewing industry, even in areas that are not traditionally associated with hops and brewing. This article attempts to give a general overview of the different areas of hop research while assessing the latest advances in hop science and their impact on brewing.

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“…Both the metabolic pathways and morphological features of hop glandular trichomes have been studied. For example, Roberts and Stevens (1962) documented the biosynthetic pathway of the essential oils while Mori (1961) documented resin biosynthesis. Moreover, Oliveira and Pais (1988) reported morphological changes in glandular trichomes with development.…”

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confidence: 99%

Two distinct phase of glandular trichome development in hop (Humulus lupulus L.)

Sugiyama

Oda

Kurosaki

2006

Plant Biotechnology

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Hop bitter resins and essential oils are biosynthesized and accumulated in lupulin glands of hop (Humulus lupulus L.). Valerophenone synthase (VPS) is involved in the first steps of biosynthesis of bitter resins, and the VPS gene is specifically expressed in lupulin glands on bracteoles and leaves. In this study, spatial and temporal expression of the VPS gene was studied using in-situ hybridization. No gene signals were observed in the early stage of lupulin gland development, but strong expression was observed when the cuticle was slightly detached from the glandular head cells. Expression levels were remarkably reduced with accumulation of hop bitter resins and essential oils in the sub-cuticular space. The findings suggest that development of lupulin glands is strictly divided into a growth phase and biosyntheticsecretory phase.

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Composition and Biogenesis of Essential Oil of Hops

Abstract: A scheme for the biosynthesis of the terpenoid constituents of the essential oil in ripening hop cones is put forward so far as current knowledge of their composition permits.

Cited by 19 publications

References 29 publications

Identification and Characterization of Geranic Acid as a Unique Flavor Compound of Hops (Humulus lupulus L.) Variety Sorachi Ace

Identification and Characterization of Geranic Acid as a Unique Flavor Compound of Hops (Humulus lupulus L.) Variety Sorachi Ace

Humulus lupulus- a story that begs to be told. A review

Two distinct phase of glandular trichome development in hop (Humulus lupulus L.)

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