Effects of Bordeaux Mixture (Copper Sulfate) Treatment on Blackcurrant/Muscat-Like Odors in Hops and Beer

Morimoto, Masahito; Kishimoto, Toru; Kobayashi, Minoru; Yako, Nana; Iida, Ayako; Wanikawa, Akira; Kitagawa, Yasushi

doi:10.1094/asbcj-2009-1118-01

Cited by 12 publications

(25 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…From the sensorial point of view, several hop cultivars as Nelson Sauvin and Cascade analysed by GC‐olfactometry exhibited rhubarb, blackcurrant bud and grape fruit notes and these odours have been linked with the occurrence of both 4MMP and 3MH . These thiols occurred in hops at ppb levels and might be affected by several field treatments like the copper treatments on the plants . Actually, the presence of copper in this type of treatment might oxydize a part of thiol into the corresponding disulfides or metal‐complexes.…”

Section: Introductionmentioning

confidence: 99%

First identification and quantification of glutathionylated and cysteinylated precursors of 3‐mercaptohexan‐1‐ol and 4‐methyl‐4‐mercaptopentan‐2‐one in hops (Humulus lupulus)

Roland¹,

Viel²,

Reillon³

et al. 2016

Flavour & Fragrance J

View full text Add to dashboard Cite

Since ten years, many studies conducted on beers showed an important impact of polyfunctionnal thiols of the aroma profiles. Among them, three thiols responsible for blackcurrant bud, passion fruit, citrus and rhubarb notes have been intensively studied: the 4‐methyl‐4‐mercaptopentan‐2‐one (4MMP), the 3‐mercaptohexan‐1‐ol (3MH) and its corresponding acetate. Their origin was very complex in beers since they probably came from odourless precursors present either in hops or in malts. Our work focused on the formal identification of thiol precursors in hops and on their quantification. By using pure synthetic standards and mass spectrometry characterization, we formally identified for the first time the occurrence of glutathionylated conjugates of 4MMP and 3MH and the cysteinylated conjugate of 4MMP in hops. First quantification results obtained on 10 hop varieties, showed that 3MH conjugates were more ubiquitous than 4MMP ones. Conjugates of 3MH occurred at very high level until 20 mg kg‐1 in Cascade hop, which was considerably higher than concentrations found in grapes. Then, we compared the proportion of bound and free thiol fractions and we demonstrated that more than 99 % of 3MH occurred as precursors in hops. On the contrary, free 4MMP fraction represented the most important source of 4MMP in hops. Copyright © 2016 John Wiley & Sons, Ltd.

show abstract

Section: Introductionmentioning

confidence: 99%

First identification and quantification of glutathionylated and cysteinylated precursors of 3‐mercaptohexan‐1‐ol and 4‐methyl‐4‐mercaptopentan‐2‐one in hops (Humulus lupulus)

Roland¹,

Viel²,

Reillon³

et al. 2016

Flavour & Fragrance J

View full text Add to dashboard Cite

show abstract

“…The metal content of hops is established during cultivation. The use of copper-based fungicides (CBFs) on hop plants as a means to prevent fungal growth has been shown to significantly increase the copper content of hops flowers at harvest [15]. Copper is a multi-site antifungal agent, meaning the development of resistance is low and is therefore commonly used in conjunction with synthetic, single-site fungicides to prevent the development of fungicide resistance over time [16,17].…”

Section: Introductionmentioning

confidence: 99%

“…80-300 mg/kg, while US-grown varieties contained less than 20 mg/kg [18]. Even single-season treatments of hop plants with copper sulfate can increase the copper content of hops by over 800% (7.1 mg/kg to 67.9 mg/kg) [15]. The use of CBFs is often required in growing regions such as the Northeastern United States, where fungal disease pressure is more severe due to increased rainfall and relative humidity throughout the growing season.…”

Section: Introductionmentioning

confidence: 99%

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

2020

View full text Add to dashboard Cite

Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of brewing and dry-hopping using hops treated with copper-based fungicides (CBFs) on the final transition metal content of model buffer solutions and pilot-scale systems of wort and beer. Copper levels in model wort and beer solutions were elevated (105.6% and 230.4% increase, respectively) when CBF-treated hops were used. In laboratory-prepared wort, elevated copper concentrations were not observed when CBF-treated hops were used for boiling. Dry hopping of beer using CBF-treated hops led to significant increases in total copper content (ca. 75 µg/kg vs. ca. 40–50 µg/kg in the control-hopped beer) when yeast was absent from the treated beer, but not when yeast was present. It was observed that manganese levels were significantly elevated in all hopped beers (ca. 495–550 µg/kg vs. 90–125 µg/kg in the unhopped control), regardless of hop treatment. A hop varietal thiol, 4-Mercapto-4-methylpentan-2-one, was spiked into treated beers, and the rate of oxidative loss was monitored during aging. Rates of thiol loss in treated beer samples did not differ across CBF treatments but were significantly lower in unhopped controls in the absence of yeast (p < 0.0001) and correlated significantly with total manganese content of the beers (R2 = 0.4228, p = 0.0006). The rate of staling in hopped beers as measured by the rate of 1-hydroxyethyl radical generation did not differ among hop treatments, suggesting that excess copper content contributed from the hops does not negatively impact the oxidative stability of the beers. These findings suggest that brewers can use CBF-treated hops without any negative implications for the shelf stability of their beers and do not contraindicate the use of CBF in hops production when necessary.

show abstract

“…Copper has important role in formation of colloidal hazes [9]. Morimoto [10] found out tignificant differences in the contents of some compounds with blackcurrant like odors in fops and beer after treatment of kop by Bordeaux mixture. Sensorial ageing of beer significantly increases in the presence of Cu 2+ ions at concentrations below 100 μg.l -1 .…”

mentioning

confidence: 99%

“…Připisuje se jí rovněž důležitá úloha při vzniku koloidních zákalů piva [9]. Morimoto [10] zjistil významné změny v obsahu ně kolika látek s charakterem aroma černého rybízu ve chmelu i pivu po ošetření chmelnic Bordeaux skou jíchou (směsný roztok síranu měďnatého a oxidu vápenatého). Senzorické stárnutí piva vý znamně narůstá v přítomnosti iontů dvojmocné mědi při koncentracích niž-ších než 100 μg.l -1 .…”

unclassified

Content of elementary copper in hops after repeated applications of copper fungicides.

Krofta¹,

Ježek²,

Kudrna³

2011

Kvasny Prum

View full text Add to dashboard Cite

Klíčová slova: chmel, měď, peronospora chmelová, fungicidy  1 ÚVOD Peronospora chmelová (Pseudoperonospora humuli L.) je v současné době nejzávažnější houbovou chorobou chmele. Způsobuje poměrně velké ztráty ve výnosu i kvalitě sklizeného chmele. Parazituje výhradně na chmelu, u něhož může napadnout kořeny i nadzemní orgány. První pří znaky napadení chmele peronosporou se mohou objevit již na mladých výhonech brzy z jara. Listy mají žluto-zelenou barvu, jsou zakrslé a zkrácením internodií dochází k jejich nahloučení. Svým vzhledem připomínají klas, a proto se běžně nazývají jako "klasovité výhony chmele" (obr. 1). Na spodní straně listů klasovitých výhonů se vytváří šedofialový povlak složený z plodonošů a letních výtrusnic. Klasovité výhony se tvoří na jaře po infekci zimními výtrusy a jsou hlavním zdrojem pro další šíření choroby na listech. Během vegetace se peronospora chmelová šíří hlavně letními výtrusy (zoosporangiemi), které vznikají nepohlavní cestou na spodní straně listů. Dostanou-li se vyzrálá zoosporangia do vlhkého prostředí, uvolňují výtrusy (zoospory), které po krátké době začí nají klíčit. Klíčící vlákénka mycelia se snaží prorůst do průduchu listů, a tak infikovat rostlinu [1]. V průběhu vegetace dochází k infekci nejen listů, ale i květů a hlávek chmele. Vzhled chmelových hlávek napadených peronosporou chmelovou je na obr. 2. Parazitická houba se může rozmnožovat pohlavním i nepohlavním způsobem. Tyto změny v životním cyklu jí umožňují přetrvat nepříznivé podmínky prostředí a naopak při příznivých podmínkách se může velmi rychle šířit [2].Keywords: hop, copper, downy mildew, fungicides  1 INTRODUCTION Downy mildew (Pseudoperonospora humuli L.) is currently the most important fungal disease of hop. It can cause high losses in yield and quality of harvested hops. Downy mildew parasites exclusively on hop. It attacts roots and above ground organs as well. First symptoms of infestation appear on young sprouts in early spring. Leaves are of green-yellow colour, stunt and due to shortening of internodia they become accumulated. These are commonly called "spikes". Spikes are the main source for further spreading of the disease in the course vegetation (Fig. 1). Grey-violet coating consisting of sporangiophores and summer spores cause building up spiked leaves on the lower side. In the course of vegetation downy mildew spreads primarily by summer spores (zoosporangia), that create in non-sex way on the leaves bottom. Under wet conditions zoosporangia start to release spores that begin to germinate after a short time. Germinating fibres of mycelium grow into leaves pores and infect plants [1]. In the course of vegetation not only leaves but flowers and cones can be infected as well. Hop cones infested by downy mildew are shown on Fig. 2. Parasite fungi can multiplicate by sex as well as non-sex way. Such changes in life cycle enable the fungi to survive unfavourite weather conditions and on contrary enable fast spreading under optimal ones [2].An important regulation factor of downy mildew occurence ...

show abstract

Effects of Bordeaux Mixture (Copper Sulfate) Treatment on Blackcurrant/Muscat-Like Odors in Hops and Beer

Cited by 12 publications

References 9 publications

First identification and quantification of glutathionylated and cysteinylated precursors of 3‐mercaptohexan‐1‐ol and 4‐methyl‐4‐mercaptopentan‐2‐one in hops (Humulus lupulus)

First identification and quantification of glutathionylated and cysteinylated precursors of 3‐mercaptohexan‐1‐ol and 4‐methyl‐4‐mercaptopentan‐2‐one in hops (Humulus lupulus)

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

Content of elementary copper in hops after repeated applications of copper fungicides.

Contact Info

Product

Resources

About