Commercial Hops Research Articles

Estudos quimiométricos sobre a degradação de lúpulo em diferentes formas de estocagem usando UV-Vis, NIRS e análises por UPLC

Abstract Hops (Humulus lupulus L.) are one of the vital raw materials of brewing and their form of storage directly influences the final organoleptic sensations of beers. When hops are incorrectly stored, the degradation of important bitter compounds occurs fast. In the present work, it was used the ultraviolet/visible and near infrared regions, maximized by Ultra-Performance Liquid Chromatographic (UPLC) analyses, to identify the best way to store hops, by varying the (i) storage temperature, (ii) contact with atmospheric air, and (iii) storage time. For that, three different varieties of commercial hops were stored for six months (Hersbrucker, Magnum and Zeus). The chemometric results obtained with the Ultraviolet/ Visible (UV-Vis) and Near Infrared Spectroscopy (NIRS) data demonstrated the hop degradation kinetics under different storage conditions, while the chromatographic results provided the quantification of this degradation. Together, the results indicated that hops stored at low temperatures (≤ -10 °C) under a vacuum plastic bag presented the lower α - acids degradation rates over the months of the study.

Portuguese wild hop diversity assessment by fast SNP genotyping using high-resolution melting.

A set of seven SNP markers was used to evaluate the genetic diversity of wild Portuguese hops in comparison with commercial cultivars. A collection of 110 wild genotypes and 33 cultivars was characterized by a high-resolution melting analysis of short amplicons targeting SNP loci. Most of the 143 genotypes (75%) could be differentiated. Phylogenetic analysis showed three main clusters, one included almost exclusively (98%) wild accessions, being the others constituted of both wild and commercial genotypes. The study of population genetic structure placed the accessions into three genetic units, being one exclusively of Portuguese genotypes. The study showed the great biodiversity of the Portuguese hop germplasm and the notable differences (FST = 0.163, p<0.00001) from commercial hops. Results support the usefulness of the use of these seven markers for hop discrimination, with the fast and high-throughput HRMA technique for allele calling and contribute to the affirmation of the high richness breeding potential of Portuguese wild hops.

Assessment and Determination of Bittering Agents, Essential Oils, and Antioxidants of Gesho (Rhamnus prinoides L. Herit) Collected from Amhara Region, Ethiopia

Rhamnus prinoides (Gesho) is an angiosperm dioecious plant, which is used for cash income, as a bittering agent for the preparation of the local alcoholic beverage and medicinal values. Although it has intense use, still its practical application is limited for local alcoholic beverage preparation, and there is no sufficient scientific report on the level and quantity of bittering agents, essential oils, and antioxidants of this plant. Therefore, the objective of this research was to assess and determine the bittering agents, essential oils, and antioxidants of R. prinoides. The leaves of R. prinoides were collected from eleven different sample sites and allowed to sun dry and then powdered. It was further dried in an oven at 60°C for 1 h, and then, total resin, essential oils, alpha acid, iso-alpha acid, beta acid, flavonoids, and polyphenols of R. prinoides were determined. All the data were analyzed using SPSS version 20.0. Based on this study finding, (16.03 ± 0.03–17.05 ± 0.04%) total resins, (10.00 ± 0.08–11.23 ± 0.07%) soft resins, (5.65 ± 0.11–6.40 ± 0.35%) hard resins, (1.82 ± 0.11–3.14 ± 0.02 mg/l) alpha acids, (2.26 ± 0.15–4.15 ± 0.10 mg/l) iso-alpha acids, (2.62 ± 0.04–4.29 ± 0.08 mg/l) beta acids, (7.74 ± 0.11–12.47 ± 0.13%) essential oils, (23.00 ± 0.14–25.01 ± 0.09%) flavonoids, and (2.11 ± 0.01–2.41 ± 0.02%) polyphenols were obtained in the leaves of R. prinoides. R. prinoides leaves taken from Tikledingay has shown statistically ( P ≤ 0.05 ) significant amount of soft resin (11.23 ± 0.07%), alpha acid (3.14 ± 0.02 mg/l), iso-alpha acid (4.15 ± 0.10 mg/l), essential oils (12.47 ± 0.13%), flavonoids (25.01 ± 0.09%), and polyphenols (2.41 ± 0.02%) in comparison with other samples. Generally, R. prinoides is a good source of bittering agents, essential oils, and antioxidants. However, the quantity of bittering agents, essential oils, and antioxidants in the leaves of R. prinoides was varied with sample collection sites. So R. prinoides can be used as a substitute for commercial hops used in the breweries, and promotion should be done to introduce the potential of Gesho as a bittering agent, source of aroma and flavor, and also antioxidant for beer and other alcoholic beverages.

Differentiation of aromatic, bittering and dual-purpose commercial hops from their terpenic profiles: An approach involving batch extraction, GC–MS and multivariate analysis

Terpenes are one of the main classes of compounds in hops (Humulus lupulus, L). They play an important role in brewing due to their central function, which is related to beer aroma. A screening of terpenes in several commercial hop varieties was carried out by gas chromatography coupled to mass spectrometry after employing a simple, straightforward and high throughput extraction method. A single batch extraction, using hexane as solvent, was employed to obtain the terpenic fraction of the hop samples. Nineteen terpenes were identified in analyzed samples with β-myrcene (2.22–45.30%), α-humulene (20.20–67.64%), and β-caryophyllene (9.97–24.62%) being the major terpenes in all samples. The studied system was multivariate modeled by principal component analysis. Based on the proposed approach, it was possible to correlate the terpenic hop profiles to their specific purpose in the brewing industry and to distinguish aromatic hops (high α-humulene content), bittering hops (high β-myrcene content), and dual-purpose hops (more complex and intermediate terpenic profile) among the samples.

Quantitative Analysis of Prenylated Constituents in Commercial Hops Samples Using Ultrahigh-Performance Supercritical Fluid Chromatography.

The importance of hops (the flowers of Humulus lupulus) as food and an herbal remedy is reflected by a large number of analytical methods published. However, supercritical fluid chromatography, a highly efficient, rapid, and "green" separation technique, has not been considered for hops samples so far. This prompted us to establish the first supercritical fluid chromatography-based protocol for the separation, identification, and quantitation of five prenylated constituents of hops. Hulupinic acid ( 1: ), a prominent oxidation product of hop acids, three flavanones, i.e., 8-prenylnaringenin ( 2: ), 6-prenylnaringenin ( 3: ), and isoxanthohumol ( 4: ), as well as the chalcone xanthohumol ( 5: ) could be baseline separated in lessthan 5 minutes using a Viridis BEH 2-EP column (3.0 × 100 mm; 1.7 µm particle size) and a mobile phase consisting of CO2 and isopropanol. Good results regarding selectivity, accuracy (recovery rates: 85.0 - 113.1%), precision (intra-day ≤ 2.1%, inter-day ≤ 3.5%), and linearity (R2 ≥ 0.99) were obtained for both photodiode array and mass detection. The lowest detection limit at 220 nm was at 0.1 µg/mL ( 1, 3: , and 4: ), with mass detection even at 0.001 µg/mL ( 4: ). As an application example of the validated method, the five hops constituents were quantified in three dietary supplements, one herbal medicinal product, and two batches of hop flowers (Lupuli flos). In most samples analyzed, the major component was 5: (0.01 - 1.02%), whereas the major component in Lupuli flos samples was compound 1: (0.12 - 0.21%). This protocol offers a fast and environmentally friendly alternative to liquid chromatography for the quality control of hops.

Development and research of the tower for hanging supports on hop-gardens

In recent years, in the conditions of economic sanctions and food embargo in Russia, the issue of import substitution has become acute. These phenomena are directly related to agricultural products and, in particular, to the production of hops. Currently, about 90% of commercial hops are imported to the Russian market from abroad. Current trends in the improvement of modern hop-growing technology require the introduction of high-tech innovations into the cultivation process. Its productivity and product quality depend on timely and proper technological operations in the production of hops. Given the increasing prices of energy, it is necessary to introduce improved low-cost technologies in the production of hops. The most important aspect at the present stage is the mechanization of such a process as hanging supports using mobile towers. The use of these towers can increase productivity in this operation in 5-6 times compared to manual labor. The tower must contain a horizontal frame with a trailed device, a working platform, hydraulic cylinders for its lifting, a system of guide rings for support beams. A small ladder should be provided for lifting workers to the site. As a result of the design, the optimal parameters of the scissor-type perspective tower were determined, providing the required stability, both static and dynamic.

Characterization of Hops (H. lupulus) Mildew Infection using Transcriptomics

Humulus lupulus, commonly known as the common hop, is a twining vine in the Cannabaceae family that produces a flower, or cone, primarily used in the manufacture of beer. H. lupulus, like other plants, suffers from pathogenic infection. Two of the most devastating fungal infections in hop plants are downy and powdery mildew. Powdery mildew is caused by the fungus Podosphaera macularis and downy mildew by the fungus Pseudoperonospora humuli. These two pathogens can rapidly infect an entire commercial hops crop and can cost commercial producers a significant amount of money. These pathogens are fairly well characterized, but the currently known antifungal treatments available have mixed results in saving hops crops. Comparatively little is known about the effect these pathogens have on H. lupulus at the molecular level. Understanding these pathogens' effect on H. lupulus at the molecular level could give us information on how to better treat infected plants or even generate resistant hop strains.In this project, we are seeking to characterize a hop mildew infection utilizing transcriptomics. Current work focuses on the reliable identification of hop plants suspected to be infected with downy or powdery mildew using molecular tools. Specifically, we are utilizing primers targeted to the rDNA of these fungal pathogens to perform PCR on genomic DNA samples from combined plant/fungus extracts. We have found that in our plant samples the primer set designed to amplify rDNA specific to P. macularis produces two unique bands at 800 and 1200 basepairs. While these bands are different from those predicted based on previous literature (Patzak 2005), they are consistent and replicable across several candidate infected plants. These bands are currently being excised and purified to be sequenced to provide additional information with respect to the specifcity of these PCR results for P. macularis identification. We have been thus far unable to generate reliable molecular markers for the identification of P. humuli.Once an infected plant has been identified by molecular means, the total RNA from the plant is extracted and reverse transcribed to cDNA. This cDNA is then sent off to be sequenced. In our results, we are looking for increases in the expression of genes related to the plant's defense response similar to A. thaliana genes previoulsy implicated in such a response, including PAD4, EDS1, and PR1 (Howard et al., 2013). We also seek transcripts from the mildews that are expressed in the infected samples that are correlated with poor outcomes for H. lupulus viability. We may also learn about some alternative splicing events that were previously unknown in hops (Howard et al., 2013). Genes of interest or genes that are expressed at an abnormal level will be further investigated to better understand their function with respect to pathogenesis and defense. Overall, this research will reveal new perspectives on the pathogenic fungi's effect on hops at a molecular level and how we may be able to combat the fungi in a novel way by understanding their transcriptomes.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Antioxidant Capacity and Total Phenol Content in Hop and Malt Commercial Samples

AbstractThe antioxidant properties of commercial hops and malted barley were evaluated by electroanalytical methods and compared with spectrophotometric methods. Hop group showed better antioxidant capacity and total phenols content (TPC) values than malt group. The highest electrochemical Index (EI) was observed for HCO hop sample. Electrochemical Index (EI) showed a good Pearson correlation with ABTS (2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulphonic acid)), DPPH (2,2‐diphenyl‐1‐picrylhydrazyl), and TPC, being of 0.85, 0.77 and 0.86 respectively for hop samples. While for the malt samples were 0.96, 0.69 and 0.49, respectively. The samples were compared to each other within each group and statistical differences can be observed, p&lt;0.05. Therefore, the electroanalytical tools showed to be practical and easy to evaluate the antioxidant properties of hop and malt samples. The results may contribute to the selection of raw material for brewing and therefore with the quality of one of beverage one most consumed around the world.

Cultivated grapevines represent a symptomless reservoir for the transmission of hop stunt viroid to hop crops: 15 years of evolutionary analysis.

Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics.

Potential African Substitutes for Hops in Tropical Beer Brewing

The potential of four selected tropical vegetables, Grongonema latifolium (Utazi), Vernonia amigdalina (Bitter leaf), Azadirachta indica (Neem) and Garcinia cola (Bitter Kola) as substitutes for hops in tropical beer brewing were evaluated. The vegetables were processed into powder by drying at 50°C for 24 hours (such that they maintained their original colour) and then cooled in dessicator before milling in a hammer mill. Proximate analysis showed that these vegetables had protein and crude fibre values comparable to those of commercial hops. Fat content values were however much higher than those for hops with Grongonema latifolium having the highest values of 19.10%. Garcinia cola with a total resin value of 8.24% and an essential oils value of (1.16ml/ 100g) had values which were significantly different from those of hops. The other three had values comparable to those for hops. Bitterness levels were high when the vegetables were extracted with organic solvents, than with distilled water. These values however decreased, the longer the storage period. Losses in bitterness were more when the vegetables were stored at ambient temperature than when they were stored at refrigeration or freezing temperatures. Losses in bitterness were more for water extracts than for organic solvent extracts. Key Words: Hops, Resins, Essential Oils, Bitterness level Journal of Food Technology in Africa Vol.9(1) 2004: 13-16

Mite abundance and phenology on commercial and escaped hops in Washington State, USA

The abundance and phenology of two-spotted spider mite (Tetranychus urticae) and its phytoseiid and nonphytoseiid predators, were monitored monthly on commercial (pesticide-treated) and escaped (pesticide-free) hops in the Yakima Valley, Washington over two seasons. Mean abundance of T. urticae for both seasons was generally low (2.8-27.7 mites/leaf) and did not differ significantly between commercial and escaped hop sites, despite application of up to four miticides at commercial sites. Miticide control of T. urticae failed at three hop yards in 1999 producing substantial populations (300/leaf) in August. Six phytoseiid species (Galendromus occidentalis, Neoseiulus fallacis, Typhlodromus pyri, Amblyseius andersoni, Typhlodromus caudiglans, Proprioseiopsis lindquisti), were identified with G. occidentalis and N. fallacis accounting for > 95% of phytoseiids sampled. Mean abundance of phytoseiids for both seasons did not differ significantly between commercial and escaped hops. Six nonphytoseiid predators of T. urticae were recorded with the mite-eating ladybird, Stethorus picipes, most abundant. The incidence of nonphytoseiid predators was more than three times greater in escaped than in commercial hops. The possible importance and utilization of an assemblage of natural enemies containing phytoseiid and nonphytoseiid predators for biological control of T. urticae populations in Washington hops, is discussed.

Habitat and Variability of Humulus lupulus var. lupuloides in Upper Midwestern North America: A Critical Source of American Hop Germplasm

traits, and survival status of this taxonomic variety are the subjects of this study. Native Humulus populations were typically associated with only a few tree and shrub species, notably Acer negundo L. [box elder], Crategus spp. [hawthorn], Fraxinus nigra Marsh. [black ash], F. pennsylvanica Marsh. [green ash], Populus balsamifora L. [balsam poplar], P. deltoides Marsh. [cottonwood], Prunus americana Marsh. [wild plum], P. pensylvanica L. [pin cherry], P. virginiana L. [choke cherry], Quercus macrocarpa Michx. [bur oak], Ribes spp. [wild currant], Rosa spp. [wild rose], Salix spp. [willow], Sambucus canadensis L. [elder], Symphoricarpos occidentalis Hook. [snowberry], and Viburnum opulus var. americanum Ait. [highbush cranberry]. Cone (strobilus) variations, exceeding those of leaves and vines, included size (15 mm to 45 mm long), shape (globose to ovoid-conical), and compactness (loose vs. imbricated bracts). Trait diversity of seedling progenies exceeded that of each native population from which they originated. Traits of genetically potential usefulness included dwarf plant habit, precocious cone production, early season flowering, pest repellence, frost resistance, potential drought resistance, and commercially desirable cone structure. Both native-plant and progeny populations were generally free of diseases common to commercial hops, thus offering germplasm that is compatible with institutional hop breeding programs. Persistence of native hop populations from 1989 to 1999 was problematic, with five of 11 selected study sites sustaining complete loss or serious damage. Protection of sensitive riparian habitats occupied by this genetic resource may be warranted, particularly until adequate germplasm sources are secured and reposited for further investigation and use.

Functional properties of hop polyphenols.

The cultivated hop (Humulus lupulus L.) is a dioecious plant of the Cannabaceae family, which is grown in most of the temperate climate zones of the world. The day-length requirements, related to the amount of light hops needed during the growing season for flowering, restrict commercial cultivation of hops to a latitude between 35° and 55° in both hemispheres. The main commercial cultivars of interest to the worldwide market are grown in Europe and the North-west region of the United States of America in the Northern Hemisphere, and in Australia, New Zealand, and South Africa in the Southern Hemisphere. The most important commercial hops (ca. 40 varieties) are all cultivars of the Humulus lupulus L. species (table 1). The only other species, Humulus japonicus L., is an ornamental plant. Wild hops are found ubiquitously.

Direct organogenesis in hop - a prerequisite for an application ofA. tumefaciens-mediated transformation

The regeneration ability of primary explants derived from mericlones of two commercial Bohemian hops was investigated. It was found that these hops are able to regenerate shoots by direct organogenesis on media containing BAP or zeatin at concentrations 0.5–2 mg dm−3. The highest regeneration of shoots was achieved from either petioles or internodes at frequencies 21% and 52%, respectively, on the medium containing zeatin (2 mg dm−3), while relatively low amount of regenerated shoots (1.3%) was observed for leaf blade explants. On the other hand, more efficient rooting occurred on the leaf blades then on other explants. A similar pattern of regeneration we observed for HLVd-infected mericlones of clone Osvald 31 even though viroid concentration inin vitro cultures was about 8-fold higher than in field-grown plants and was 31.1 pg mg−1 of fresh mass in the average. These results suggest that HLVd infection did not impair organogenesis. We found that high 2,4-D concentration pretreatment (11 mg dm−3) did not promote somatic embryogenesis. Although this treatment suppressed direct organogenesis, the inhibition was not complete and in low frequency the shoot regeneration was seen. Sensitivity of hop explants to antibiotics commonly used inAgrobacterium-mediated transformation was assayed. It was found that kanamycin (100–200 mg dm−3) suppressed efficiently callogenesis, root formation and shoot proliferation. An estimation of effect of kanamycin (200 mg dm−3) and ticarcillin (500 mg dm−3) on morphogenesis was performed using regeneration medium. The inhibitory effects observed suggest that these conditions could be used inAgrobacterium transformation/selection system.

Control of Spider Mites on Hops, Idaho, 1984

Abstract Miticides were applied as foliar sprays on commercial hops near Caldwell, Idaho. Each plot was .01 acre, 9 hills. Treatments were arranged in a randomized complete block design with 4 replicates. Miticides were applied 3 Aug ’84 using a Solo Air Blast Mist Blower at 50 gal/acre. Mite counts were made by randomly picking 10 leaves per replicate. Leaves were brushed through a brushing machine and mite counts were made under a dissecting microscope.

Methods for Determining the Percentage of Seeds, Strigs, Stems, and Leaves in Commercial Hops1

Agronomy JournalVolume 31, Issue 8 p. 698-702 Article Methods for Determining the Percentage of Seeds, Strigs, Stems, and Leaves in Commercial Hops1 C. G. Monroe, C. G. MonroeSearch for more papers by this authorD. D. Hill, D. D. Hill Graduate Assistant and Associate Agronomist, Farm Crops Department, Oregon State College, respectively.Search for more papers by this author C. G. Monroe, C. G. MonroeSearch for more papers by this authorD. D. Hill, D. D. Hill Graduate Assistant and Associate Agronomist, Farm Crops Department, Oregon State College, respectively.Search for more papers by this author First published: 01 August 1939 https://doi.org/10.2134/agronj1939.00021962003100080006x 1 Published as Technical Paper No. 312 with the approval of the Director of the Oregon Agricultural Experiment Station, Corvallis, Ore. Contribution of the Department of Farm Crops. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume31, Issue8August 1939Pages 698-702 RelatedInformation