Hop Extracts-a Review

Laws, D. R. J.

doi:10.1002/j.2050-0416.1981.tb03980.x

Cited by 13 publications

(9 citation statements)

References 22 publications

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“…Mucopolysaccharides could not be found in the secretion of hop trichomes, which agrees with the results obtained from chemical analysis (Verzele 1979, Pfenninger et al 1979, Laws 1981). …”

Section: Discussionsupporting

confidence: 89%

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Glandular trichomes of Humulus lupulus var. Brewer's Gold: Ontogeny and histochemical characterization of the secretion

Oliveira

Salomk

Pais

1988

Nordic Journal of Botany

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Leaves of Humulus lupulus possess two types of glandular trichomes: -peltate (lupulin) and bulbous. Peltate trichomes are formed from a protodermal cell by two anticlinal divisions in perpendicular planes, followed by two periclinal ones that give rise to the initials of the head cells, the basal and the stalk cells. Head cells divide successively in radial and irregular planes. Fully developed peltate trichomes are built of a glandular head consisting of 30 to 72 cells, four stalk cells and four basal cells. Bulbous trichomes are also formed from a protodermal cell by an anticlinal division followed by two periclinal ones that produce the initials of the glandular head cells, and the basal and stalk cells. Fully developed bulbous trichomes consist of four (occasionally eight) head glandular cells, two stalk cells and two basal cells. The density of peltate trichomes decreases with the expansion of the leaves. Both peltate and bulbous trichomes secrete essential oils. Peltate trichomes are the preferential site for the synthesis of bitter resins. Tannic acids could not be detected histochemically either in peltate or in bulbous trichomes. Both types of trichomes produce secretion that accumulates in the subcuticular space, being released, in the case of bulbous trichomes, by rupture of the cuticle.

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“…Mucopolysaccharides could not be found in the secretion of hop trichomes, which agrees with the results obtained from chemical analysis (Verzele 1979, Pfenninger et al 1979, Laws 1981). …”

Section: Discussionsupporting

confidence: 89%

“…The negative results obtained with the reagents for alkaloids suggest that these compounds are absent from hop glandular trichomes, which agrees with the chernical analysis (Verzele 1979, Pfenninger et al 1979, Laws 1981.…”

Section: Discussionsupporting

confidence: 82%

Glandular trichomes of Humulus lupulus var. Brewer's Gold: Ontogeny and histochemical characterization of the secretion

Oliveira

Salomk

Pais

1988

Nordic Journal of Botany

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“…Uvádí se, že destilace za atmosférického tlaku vede k degradativním změnám aroma, takže aroma výsledné silice neodpovídá vůni původního chmele (Rettberg et al, 2012). Extrakční postupy používají k izolaci silic organická rozpouštědla jako je například hexan, ethanol, trichlorethylen nebo methylenchlorid (Laws, 1981). Při odpařování rozpouštědla však dochází ke ztrátám nejtěkavějších složek, což vede ke změnám charakteru aroma získané silice (Pickett, 1975).…”

Section: Metody Pro Ověřování Autenticity Odrůd Chmele -účInný Nástrounclassified

“…Distillation under atmospheric pressure has been reported to lead to degradative changes in aroma so that the resultant oil aroma does not match the aroma of the original hops (Rettberg et al, 2012). Extraction procedures use organic solvents such as hexane, ethanol, methylene chloride or trichlorethylene (Laws, 1981) for the isolation of essential oils. Solvent evaporation, however, causes losses of the most volatile components, which leads to changes in the character of the resulting oil (Pickett, 1975).…”

Section: Metody Pro Ověřování Autenticity Odrůd Chmele -účInný Nástromentioning

confidence: 99%

Methods for verifying the authenticity of hops - an effective tool against falsification

Olšovská¹,

Krofta²,

Jandovská³

et al. 2016

Kvasny Prum

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■ 1 ÚVODAutenticita potravin je termín, který jednoduše označuje, zda potraviny nakupované spotřebitelem odpovídají jejich popisu, a je aktuálním tématem v nejrůznějších potravinářských komoditách. Proto je v současné době věnováno mnoho pozornosti a jsou vynakládány nemalé fi nanční prostředky na vývoj analytických metod pro ověřo-vání autenticity potravin, nápojů a jejich surovin.Také chmel je komodita, ve které dochází k falzifi kaci původu a odrůd, což může ve velké míře ovlivnit senzorický profi l piva z něho vyrobeného. Žatecký poloraný červeňák (ŽPČ) je na trhu všeobec-ně považován za světový standard kvality v kategorii aromatických chmelů. Prvotřídní kvalitě odpovídá i vyšší cena. V uplynulých letech bylo zaznamenáno několik opakovaných případů jeho falzifi kace. Falzifi kace Žateckého poloraného červeňáku ve formě granulí byla Recenzovaný článek / Reviewed Paper Olšovská, J., Krofta, K., Jandovská, V., Patzak, J., Štěrba, K., 2016: Metody pro ověřování autenticity chmele -účinný nástroj proti falzifi kaci. Kvasny Prum. 62, č. 10, s. 294-305 K pokusům o falzifi kaci dochází téměř u všech komodit a výjimkou není ani chmel. Je proto nezbytné hledat způsoby, jak ověřovat jeho autenticitu. Přehledový článek shrnuje moderní metody pro ověřování autenticity chmele a uvádí rovněž nejnovější výsledky spolupráce Výzkumného ústavu pivovarského a sladařského, a.s. a Chmelařského institutu, s.r.o., v Žatci. K ověřování autenticity chmele se používají metody chemotaxonomické a genetické. V roce 2015 byly provedeny chemické analýzy novošlechtěných hybridů pro České pivo (obsah a složení alfa a beta kyselin, obsah a složení chmelových silic, obsah celkových polyfenolů) a byly provedeny molekulárně-genetické analýzy 150 vybraných genotypů chmele ze světového sortimentu a šlechtitelského materiálu. Pomocí výsledků byl z testovaných genotypů sestaven přehledný dendrogram. Autoři se dále zabývali profi lováním českých odrůd chmele na základě chemických profi lů proanthokyanidinů a podařilo se jim pomocí klastrové analýzy jasně odlišit odrůdy chmele včetně jejich genetické příbuznosti.Olšovská, J., Krofta, K., Jandovská, V., Patzak, J., Štěrba, K., 2016: Methods for verifying the authenticity of hops -an effective tool against falsifi cation. Kvasny Prum. 62, No. 10, pp. 294-305Falsifi cation attempts occur in almost all commodities and hops is no exception. It is therefore necessary to look for ways to verify its authenticity. This review summarizes modern methods for verifying the authenticity of hops and also provides the latest results of the collaboration of the Research Institute of Brewing and Malting, PLC. and the Hop Research Institute, Ltd., in Žatec. Chemotaxonomic and genetic methods are used to verify the authenticity of hops. Chemical analyzes of newly bred hybrids potentially suitable for Czech beer focused on the content and composition of alpha and beta acids, content and composition of hop oils, and content of total polyphenols were performed and molecular genetic analyses of 150 selected hop genotypes in...

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“…Over the years, hop extracts have been used to replace hop powders or pellets in brewing, ensuring the following advantages: better bitterness control between different batches owing to their greater homogeneity, improved hop utilization due to the use of concentrated extracts, improved stability during the storage, which allows the preservation of excess production from one season to the next, and reduced transport and storage costs [10]. Hop extracts consist of a resinous fraction, responsible for the bitter taste of the beer and a volatile fraction that influences the aroma [11].…”

Section: Introductionmentioning

confidence: 99%

Using Hydrofluorocarbon Extracts of Hop in a Pilot Scale Brewing Process

et al. 2022

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In recent years, the use of hop extracts in industrial and home brewing processes as an alternative to hop cones or pellets usually added to wort during boiling has become increasingly popular. These extracts represent concentrated sources of bitter compounds, i.e., α- and β-acids, which are involved in some of the main reactions that take place in the wort and are responsible for the bitterness and the final quality of beer. This work aims at proposing a novel extraction technique, using a hydrofluorocarbon solvent in subcritical conditions; this process provided an extraction yield of 19% and an α-acid recovery of approximately 49% in 120 min of process. The α-acid isomerization kinetics of thermally treated hop extracts were studied and compared with those of both hop pellets and a CO2 extract. Laboratory scale tests showed that shorter boiling times were needed using hydrofluorocarbon and CO2 extracts (approximately 25 min and 34 min, respectively) to reach the same isomerization efficiency of 16.73%, achieved in 50 min of boiling with pellets. Moreover, the process was scaled up and the possibility of considerably reducing the conventional treatment times using hydrofluorocarbon extracts was confirmed: the same isomerization yield (9.1%) obtained after 50 min using the traditional procedure with hop pellets was reached in a shorter time of approximately 35 min in a pilot apparatus.

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Hop Extracts-a Review

Abstract: The production and use of both hop extracts and isomerized hop extracts is reviewed with particular reference to recent advances in hop extract technology.

Cited by 13 publications

References 22 publications

Glandular trichomes of Humulus lupulus var. Brewer's Gold: Ontogeny and histochemical characterization of the secretion

Glandular trichomes of Humulus lupulus var. Brewer's Gold: Ontogeny and histochemical characterization of the secretion

Methods for verifying the authenticity of hops - an effective tool against falsification

Using Hydrofluorocarbon Extracts of Hop in a Pilot Scale Brewing Process

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