Brewers Gold Research Articles

Biologically Active Extracts from Different Medicinal Plants Tested as Potential Additives against Bee Pathogens.

Honey bees (Apis mellifera) perform pollination service for many agricultural crops and contribute to the global economy in agriculture and bee products. However, honey bee health is an ongoing concern, as illustrated by persistent local population decline, caused by some severe bee diseases (e.g., nosemosis, AFB, EFB, chalkbrood). Three natural recipes are in development based on the bioactive compounds of different plants extract (Agastache foeniculum, Artemisia absinthium, Evernia prunastri, Humulus lupulus, Laurus nobilis, Origanum vulgare and Vaccinium myrtillus), characterised by HPLC-PDA. The antimicrobial activity of these recipes was tested in vitro against Paenibacillus larvae, Paenibacillus alvei, Brevibacillus laterosporus, Enterococcus faecalis, Ascosphaera apis and in vivo against Nosema ceranae. A mix of 20% blueberry, 40% absinthium, 10% oakmoss, 10% oregano, 10% Brewers Gold hops, 5% bay laurel and 5% anise hyssop extract showed the strongest antibacterial and antifungal activity. Combing several highly active plant extracts might be an alternative treatment against bee-disease-associated parasites and pathogens, in particular to replace synthetic antibiotics.

Efficacy of Natural Formulations in Bovine Mastitis Pathology: Alternative Solution to Antibiotic Treatment.

IntroductionBovine mastitis is an inflammatory disease of the udder that causes important economic losses in the animal breeding and dairy product industries. Nowadays, the conventional livestock antibiotic treatments are slowly being replaced by alternative treatments. In this context, the main aim of this study was to evaluate the efficacy of natural products in alternative treatment of bovine mastitis.Material and MethodsTwo natural formulations with previously suggested in vitro antimicrobial effect were tested in vivo on mastitic cows. Animals with a positive diagnosis for mastitis (n = 20) were divided into three treatment groups: two groups (n = 8) were administered formulations of propolis, alcoholic extracts of Brewers Gold and Perle hops, plum lichen, common mallow, marigold, absinthe wormwood, black poplar buds, lemon balm, and essential oils of oregano, lavender, and rosemary designated R4 and R7 (differing only in the latter being more concentrated) and one group (n = 4) a conventional antibiotic mixture. In vivo efficacy of treatments was evaluated by somatic cell and standard plate counts, the treatment being considered efficacious when both parameters were under the maximum limit.ResultsR7 was effective in the most cases, being therapeutically bactericidal in six out of eight cows, while R4 gave good results in three out of eight cows, and conventional antibiotics cured one out of four.ConclusionThese results suggest the possible therapeutic potential of these natural products in bovine mastitis.

Kazbek – The First Czech Aroma “Flavor Hops” Variety: Characteristics and Utilization

The world market of craft beer, especially dry hopped beers, has been constantly growing in the last few years. That is why new varieties of hops are still being bred. This article gives the genetic, agronomic, chemotaxonomic and brewing characteristics of Kazbek, the first “flavor hops” variety bred in the Czech Republic. Kazbek genetically belongs to a group of bitter American hops resulting from Brewers Gold variety, but the alpha acids content is relatively low, 5.0–8.0% by weight. The content of a homologous series of geranyl esters (acetate – propionate – isobutyrate) in an amount 2–4% of total essential oils (1–1.5 g/100g) is considered to be the originator of the specific, mainly citrus-like aroma of Kazbek. Moreover, the essential oil fraction contains about 25 sulfurous substances, predominantly thioesters. In the pilot scale brewing tests, the quality of Kazbek hops was proved both in kettle and dry hopping of Pilsner lagers. The overall sensory impression of kettle hopped lagers was comparable to Saaz hops, the differences were in the character of hop-derived flavor and bitterness. The best results of dry hopped beers were achieved for a 2.5 g/l hop dose and a contact time of 3 days.

Utilization of molecular methods for hop (Humulus lupulusL.) genotype evaluation

In recent years, the utilization of molecular genetic methods is the best tool for the evaluation of individual genotypes. Modern molecular methods allow us to check the changes caused by the combination of parents, evaluate the relationships of individual genotypes or variability (diversity) within the population. Recently, we have developed an efficient marker system to control the authenticity of Czech hop (Humulus lupulus L.) cultivars, which we introduced into the system for the identification and control of hop cultivar purity. In our presented study, we evaluated molecular genetic variability within 109 world hop cultivars by hierarchical clustering techniques and principal coordinates analysis (PCoA). For molecular analyses, we used 269 amplified marker of SSR, STS and EST-SSR loci in total. Hop cultivars were divided into two major groups with North American or European origin and breeding influence by cluster analysis, as common knowledge from previous published results. PCoA more distinguished two breeding cultivar groups of ‘Saaz’ and ‘Fuggle’ hops in Europe. The usage of some cultivars during breeding history (‘Brewers Gold’, ‘Northern brewer’, ‘Cascade’, ‘Columbus’) was also noticeable.

First report of hop latent viroid in Turkey.

This study reports the identification of hop latent viroid (HLVd) in commercial hop (Humulus lupulus L.) plants in the Pazaryeri region, Bilecik province, in Turkey. Hop plants without clear symptoms were randomly collected during 2015 and 2016 surveys. A total of 210 samples were collected from commercial cultivars Erciyes, Brewers Gold, Aroma and Ege. RNA was extracted using the GeneJET Plant RNA Purification Mini Kit and used in one step RT-PCR with specific HLVd primer pair 5’- CCACCGGGTAGTTTCCAACT-3’ and 5’-ATACAACTCTTGAGCGCCGA-3’ and protocols described by Eastwell and Nelson (2007). HLVd was detected in 20 out of 210 plant samples. The amplified DNA products of the expected size (ca. 260 nts) were purified and directly sequenced. Direct sequencing of the PCR products (Molgantec, Turkey) confirmed the presence of HLVd in these plants. Blast analyses and dendograms of HLVd sequences performed using the Mega 7 (Kumar et al., 2016) showed 97% to 98% maximum nucleotide identity with GenBank accession numbers KT600318 (Belgium) and EF613181 (China). Four HLVd isolates were graft transmitted from infected to healthy hop plants. All inoculated plants were found to be positive for HLVd in the RT-PCR tests and none of them exhibited any specific symptoms. To our knowledge, this is the first report of HLVd on hop plants in Turkey.

Biochemical indices of hop resistance to Verticillium albo-atrum and Fusarium sambucinum

The contents of total phenolic compounds, chlorogenic acid and peroxidase activity as well as monophenols to polyphenols ratio were studies in the suckers of the hops as indices of resistance to <i>Verticillium albo-atrum</i> and <i>Fusarium sambucinum</i>. The suckers of hop taken in the early spring from the healthy and infected plots were used in the experiments. As a research material were included cv. 'Northern Brewer' - a wilt tolerant variety, two wild susceptible varieties - cv. 'Lubelski' and cv. 'Brewers Gold', four breeding clones and one male plant. It was found that, 'Northern Brewer' contains more total phenolic compounds, rnonophenols and chlorogenic acid, and in particular considerably higher peroxidase activity as compared to cv. 'Lubelski'. Taking into consideration the contents of these compounds, in the majority of cases, the new breeding clones were similar to the mother variety 'Northern Brewer'. It seems resonable to assume, that the new clones should be more wilt tolerant than varieties and populations cultivated in our country.

The effects of storage temperature on the chemical composition of hop pellets

The effects of storage temperature on the composition of hop pellets of the varieties Brewers Gold, Efes Aroma, Galena, Northern Brewer and Saaz were studied. The hop pellets were stored at 3°C and room temperature for 6 months in the dark. Chemical analyses showed that there were substantial losses of alpha- and beta-acids, soft resins and hop oil in all hop varieties stored at room temperature. These hop varieties showed a significant increase in hard resins at room temperature storage. Storing these varieties at 3°C did not stop but slowed down these detrimental changes in hop composition. Changes in hop composition during storage were also dependent on the variety of hops used.

Adventitious shoot regeneration in cultures of Humulus lupulus L. (hop) cvs. Brewers Gold and Nugget

A very efficient protocol for plant regeneration from two commercial Humulus lupulus L. (hop) cultivars, Brewers Gold and Nugget has been established, and the morphogenetic potential of explants cultured on Adams modified medium supplemented with several concentrations of cytokinins and auxins studied. Zeatin at 4.56 μm produced direct caulogenesis and caulogenic calli in both cultivars. Subculture of these calli on Adams modified medium supplemented with benzylaminopurine (4.4 μm) and indolebutyric acid (0.49 μm) promoted shoot regeneration which gradually increased up to the third subculture. Regeneration rates of 60 and 29% were achieved for Nugget and Brewers Gold, respectively. By selection of callus lines, it has been possible to maintain caulogenic potential for 14 months. Regenerated plants were successfully transferred to field conditions.

The Unspecific Fraction Analysis of Romanian Hops Cultivars

The study of the chemical composition of the unspecific bitter resins was carried on for Magnum, Brewers Gold, Hüller Bitterer and Perle hops cultivars, harvest in 2008, in pedo-climatic areas of Transilvania, in the Saschiz and Seleuş farms. 
 The drying and pelletizing of whole hop cones change the composition of unspecific fraction, especially because the oxidation process. The LCV decrese from 13,44% to 9,24% in Magnum cultivar, from 8,50 to 6,99 in Brewers Gold, from 9,84 to 6,07 in Huller Bitterer and from 9,25 to 6,40% in Perle cultivars. The results were statistical analysed with ANOVA test and the results showed that the technological conditions (temperature, time) are the most important factors in bitter substances losses on technological flow of hop pellets production.

Odour intensities of hop oil components.

AbstractOlfactory thresholds of a series of compounds previously identified in Brewers Gold Hop Oil are given. Thresholds of the oxygenated components ranged from 0.3 to 28 parts per 10° while those of the hydro‐carbon fraction ranged from 6 to 140 parts per 10°. For solutions of hop oil in water, myrcene accounted for about 58% of the total odour intensity of the whole oil and 85% of the odour of the hydrocarbon fraction. The oxygenated fraction amounted to about 1/7 of the whole oil but contributed about 1/3 of total odour intensity.