Hop essential oil (HEO), extracted from the hop plant (Humulus lupulus L.), is a pivotal player in the brewing industry and presents diverse opportunities across various products. This article aims ...to underscore the uniqueness of HEO, emphasizing not only its critical role in beer production but also its aromatic and functional properties that extend beyond the brewing sector. In contrast to similar articles, this review goes beyond the traditional application of HEO in brewing and highlights its emerging role in diverse sectors such as aromatherapy, personal care products, and the food industry. The array of aromatic profiles from different hop varieties allows breweries to innovate and create a wide spectrum of unique flavors and aromas, offering a distinctive approach in the brewing landscape. The significance of this manuscript lies in addressing the increasing demand for natural and aromatic products, propelling the growth of the HEO market.
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•Hop essential oil enriches beer aroma, flavor, stability.•Hop essential oil market expansion spurs new applications.•The majority of patents (46.5 %) refer to pharmaceutical applications of hop essential oil.•Hop essential oil is used in food, pharmaceuticals, cosmetics, and animal feed.
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•The top chemical constituents of hop essential oil were β-Myrcene and humulene.•The water-soluble hop essential oil (HEO) were fabricated using nanoemulsion.•HEO nanoemulsion could ...inhibit the mycelial growth and spore germination.•The production of deoxynivalenol (DON) could be suppressed by HEO nanoemulsion.•HEO nanoemulsion altered the contents of total lipid and chitin in outer cell membrane.•The permeability of cytoplasmic membrane was also increased.
This work aims to investigate antifungal, mycotoxin inhibitory efficacy of the hop essential oil (HEO) nanoemulsion and their mode of action (MOA) against Fusarium graminearum isolate, a fungal pathogen causing Fusarium Head Light in cereal crops. The HEO, primarily consisting of terpenes and terpenoids, was encapsulated in nanoemulsion droplets. Physically stable HEO-in-water nanoemulsion was fabricated using 0.5 wt% of tween 80 and 5 wt % oil phase comprising 30% of Ostwald ripening inhibitor and 70% of HEO. In terms of antifungal effect, HEO nanoemulsion could not only effectively inhibit mycelial growth and spore germination of F. graminearum isolates, but also remarkably suppress the production of deoxynivalenol (DON) and its derivatives in rice culture by applying 750 μg of HEO/g rice. Our studies on the MOA showed that HEO nanoemulsion could alter the contents of total lipid and chitin in outer cell membrane as well as damaging cytoplasmic membrane.
In order to increase the stability of hop (Humulus lupulus L.) essential oil (HEO) and diversify its application into hot beverages, CAPSUL®, modified food starch, was used as the wall material to ...encapsulate HEO at the mass ratio of 2:1 through spray drying under 180 °C. The resultant microcapsules were applied to the non-alcoholic hop tea for the first time and their release kinetics in this matrix were analyzed by gas chromatography-mass spectrometry (GC-MS). Results showed that the reconstituted HEO emulsion possessed fine droplet size (3.295 μm) and high zeta potential (−22.50 mV). The resultant HEO microcapsules exhibited low moisture content (1.249%), suitable bulk density (0.2934 g/mL), good swelling capacity (2.235 g/g dry solids), low color difference (6.310), desirable morphological characteristics, high encapsulation efficiency (92.02–95.45%) and high flavor retention (57.13–71.15%). Each target aroma compound had its specific release behavior and mechanism from HEO microcapsules, among which β-myrcene and methyl octanoate showed the highest and lowest cumulative release respectively. This might be associated with their different volatilities, polarities, function groups and molecular sizes, or their varying hydrogen-bond formation capability at the entrance of starch helix. Most importantly, HEO microcapsules showed significant aroma increasing and stabilizing effects on the hop tea product during storage. These ideal characteristics of HEO microcapsules demonstrated the great potential of diverse essential oil microcapsules as the promising flavoring agents in a variety of hot beverage matrices.
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•Overall desirable physicochemical properties were observed in HEO microcapsules.•HEO microcapsule showed satisfactory encapsulation efficiency and flavor retention.•Each target aroma compound had a specific release mechanism during 40 °C of storage.•HEO microcapsule was an effective flavoring agent in the hot beverage matrix.
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•Hydrodistillation and subcritical CO2 extraction influence the chemical composition.•Different extraction yields were obtained from the four hop varieties.•Hydrodistillation obtained ...sesquiterpenes hydrocarbons as the main constituents.•Subcritical CO2 extraction presents oxygenated and non-oxygenated sesquiterpenes.
Hop essential oil and hop extract using carbon dioxide (CO2) are products with high added value because they have bioactive and sensory properties. In this context, the objective of this study was to obtain and characterize essential oil and extracts from pelleted hops of El Dorado, Polaris, Hallertau Blanc and Callista varieties using hydrodistillation and subcritical CO2 extraction methods. Extraction yield ranged from 0.38 % to 1.97 % (m/m) for essential oils and from 8.76 % to 15.35 % (m/m) for extracts using subcritical CO2. The chemical compositions of the essential oils were mainly monoterpene (18.14 % to 29.91 %) and sesquiterpene (46.01 % to 59.03 %) hydrocarbons and for the extracts were sesquiterpene hydrocarbons (33.05 % to 71.90 %) and oxygenated sesquiterpenes (14.80 % to 34.89 %). The extracts showed better antioxidant activity than essential oils due to the presence of phenolic compounds and flavonoids. Hop extracts showed some antimicrobial activity, but essential oils did not demonstrate antimicrobial potential. Hop extracts obtained with subCO2 have the potential to be used in the brewing industry as a flavoring and as natural antioxidants.
Hop cones (Humulus lupulus L.), or more specifically the lupulin glands, hold the reason for the specific, pleasant aroma of hops - its essential oil. The hops themselves, or the extracted oil, are ...used almost exclusively in beer production. The essential oil is an indispensable part of beer and is responsible for its characteristic aroma. However, hop essential oil (HEO) also has a broad range of positive effects on human health and is a potential natural pesticide that has no harmful impacts on humans. This review summarizes basic information about HEO, including its chemical composition and methods for extraction and analysis, while also providing a comprehensive overview of the contribution to beer aroma, health, and insecticide applications for this versatile essential oil.
Hops' unique composition of essential oil components and bitter resins are crucial for beer aroma, which is important to consumers' acceptance of beer. In this experiment the same wort was divided ...into four portions and each was hopped differently. To determine the dynamics of isomerization rates the concentrations of alpha- and iso-alpha-acids were continuously measured. Measurements of hop essential oil components were performed during each process to understand the dynamics of the transition into beer. The maximum isomerization yield of alpha-acids (18.1%) was achieved after 100 min. Longer boiling increased the reduction of iso-alpha-acids, as well as essential oil components. Dry hopping also affected not only on beer aroma but also on beer bitterness.
Hop terpenes might be oxidized during kettle boiling into more water soluble compounds that could contribute to ‘hoppy’ aroma of kettle hopped lager beers. Our current research proves that the ...boiling process induces significant changes in the hop oil volatile profile. The discrimination between volatile profiles of unboiled and boiled hop essential oil was evaluated via principal component and cluster analysis (PCA and CA). HS–SPME–GC–MS analysis revealed quantitative changes (e.g. increases in the levels of oxygenated α-humulene and β-caryophyllene derivatives) as well as qualitative changes (i.e. detection of compounds, not found in unboiled hop essential oil) in the hop oil volatile profile upon boiling. Many of these compounds were previously found in lager beer and may therefore contribute to beer flavor. Interestingly, the analytical difference between unboiled and boiled hop essential oil proved to be more pronounced as the initial hop essential oil concentration used for boiling was increased. In addition, lager beers spiked with boiled hop oil were described as ‘hoppy/spicy’ during sensory evaluations. Therefore, the newly formed products and hop oil constituents that are characterized by an increased recovery after boiling, are candidate compounds for ‘hoppy’ aroma in real brewing practice.
•Analytical discrimination between unboiled and boiled hop essential oil via multivariate statistics•Increase in levels of β-caryophyllene and α-humulene derivatives upon boiling of hop oil•Compounds formed ‘de novo’ (not present in the unboiled sample) upon boiling•Non-aromatized lager beer spiked with boiled hop oil described as ‘hoppy/spicy’ during sensory trials
In Ukraine, hops are basically processed into Type 90 pellets, that are practically indistinguishable in terms of biochemical indicators from hop cones. Pellets of hop are the single domestic source ...of hop products that can be serve as an alternative to imported pellets and extracts that used in the Ukraine brewing. Comprehensive studies of the evaluation of Type 90 hop pellets of aromatic and bitter varieties produced in Ukraine and European countries allowed establishing that they have different biochemical compositions and consequently, different brewing value. That have been identified differences in the absolute values of indicators such as the mass fraction of alpha acids, beta acids and their composition, xanthohumol, essential oil, the ratio of valuable hop compounds: beta acids to alpha acids and components of the essential oil. It has been determined that in hop pellets of aromatic varieties, the content of alpha acids changing from 3.3% in the Klone 18 variety to 5.9% in the Hallertauer Tradition variety. The content of beta acids, in the investigated pellets, ranges from 3.6% (Klone 18) to 6.7% in the Slavyanka variety. It is established that the hop pellets made from Ukrainian varieties Zagrava and Slavyanka have significantly higher content of beta acid 6.3% and 6.7%, respectively, compared to pellets of foreign varieties. There is a significant advantage in the resin fraction of beta acids over the fraction of alpha acids in the pellets of Slavyanka, Klone 18, Zhatetsky and Zagrava varieties, that they meaning retain a positive coefficient of aromaticity between the content of beta and alpha acids that ranges from 1.18 to 1.37. The content of alpha acids ranges from 8.7% in the Polisky variety to 14.1% in the Magnum variety in the hop pellets of bitter varieties. The content of beta acids in the same pellets ranges from 4.2% to 5.9%. It has been established that the composition of alpha and beta acids in the investigated pellets changes depending on the variety. It has been proven that Ukrainian-produced hop pellets correspond to their international counterparts in terms of their characteristics. Specifically, the biochemical and technological indicators of Klone 18 hop pellets correspond to the characteristics of pellets of the Czech variety Zhatetsky, pellets made from the bitter variety Alta correspond to the biochemical indicators of German Magnum pellets but pellets of varieties such as Slavyanka and Zagrava exceed the world analogies in terms of the composition and quality of bitter substances and essential oil. Based on the comparative biochemical characteristics of Type 90 hop pellets of Ukrainian and European production, the quality of Ukrainian hop products has been found to be at a global level. Certified domestic hop products, specifically Type 90 pellets, can be used do not only by Ukrainian brewers but also by other manufacturers to create new innovative and competitive products with various functional purposes.
A headspace (HS)-trap method in combination with gas chromatography (GC)–mass spectrometry (MS) was developed for the determination of volatile constituents in hops. The highly sensitive HS-trap ...system reduces the detection limit by using up to four trap enrichment cycles. Seventy hop samples of different varieties and cultivation regions, from the 2008 harvest, were examined using the HS-trap-GC-MS method and the established “European Brewery Convention” (EBC) method for hop essential oil analysis. Twenty-one different volatiles were quantified for each hop sample. For all compounds, except caryophyllene oxide, a strong correlation was found between the results of the HS-trap method and the EBC method. Experiments have revealed that the EBC method using steam distillation is not appropriate for thermolabile compounds, such as caryophyllene oxide, due to decomposition during boiling. The HS-trap method is fast and sensitive, requires small sample amounts and minimal sample preparation, and is easy to apply.
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