COMPARATIVE ESTIMATION OF THE QUALITY OF UKRAINIAN AND EUROPEAN HOP PELLETS

With the expansion of the assortment of beer, brewers increasingly use different hop products of new varieties of hop, that makes it possible to obtain beer with certain profiles of taste and aroma. The comprehensive assessment of the quality of hop pellets Type 90 produced in Ukraine and European countries and that are most demand by Ukrainian beer producers were conducted. It made possible to form a database of biochemical characteristics of fine aromatic and aromatic varieties based on the absolute values of such indicators as the mass fraction of alpha-acids and beta-acids (with including their chemical composition), xanthohumol, essential oil and its components and the ratio of certain valuable hop compounds. The mass fraction of alpha-acids in hop pellets of fine aromatic varieties was ranges from 2.7% in the Hersbrucker variety to 5.3% in the Slavianka variety. A higher indicator of the content of alpha-acids was found in the pellets of the aromatic varieties Zagrava and Tradition with a range of variation of the indicator from 4.6 to 7.2% (average values are 5.9 and 6.0%, respectively). The content of beta-acids in the studied pellets ranges from 3.6% (Lublin) to 6.6% in the pellets of the Slavianka variety. The among the studied pellets in the composition of bitter substances the proportion of beta-acids is equal or exceeds the proportion of alpha-acids. As a result, they save a positive aromaticity ratio between the content of beta-acids and alpha-acids, that ranges from 0.99 (Lublin) to 1.84 (Hersbrucker). In the samples of hop pellets that was studied there is significant variability in the essential oil content with average values from 0.49 (Klone 18) to 1.64 ml/100 g in Zagrava hop pellets. The general components of essential oil of hops are hydrocarbons that are represented by monoterpenoid - myrcene and sesquiterpenoids: caryophyllene, humulene and farnesene, that collectively set up from 66.6% to 78.8% of their total amount. Biochemical criteria for brewery assessment of hop varieties of the aromatic type have been determined and scientifically substantiated. The main ones are the content and composition of bitter substances, in particular: alpha-acids and beta-acids with an indicator value in the range of 4–9%; the ratio between the number of beta- and alpha-acids is about 1; the mass fraction of cohumulone in the composition of alpha-acids is up to 28%; the amount of essential oil per 1 g of alpha-acids is within 0.20–0.25 ml in the presence of a significant amount of sesquiterpenoids. The amount of farnesene in the composition of the essential oil was within 10–20%, the content of prenylated flavonoids, in particular xanthohumol, was at least 0.4%. A new hop variety Perlyna with characteristics that requirements the specified criteria is presented. Expanding the assortment of hop products due to the formation of highly productive hop plantations of new varieties with defined characteristics is an important prerequisite for ensuring a sufficient level of competitiveness of Ukrainian hop products on the world market.

Goal. To make a comprehensive biochemical and technological assessment of the quality of aromatic and bitter hop varieties using the example of an innovative model of farm development to ensure the production of competitive hop products. Methods. Monographic — to study the existing positive experience on the above issues; analysis and synthesis — to study the results of research, generalize, systematize, compare and draw conclusions; physicochemical — to determine with the use of high-performance liquid chromatography the amount and composition of bitter substances; conductometry — to establish the mass fraction of alpha acids; capillary gas chromatography — to study the components of essential oil (essential oil was obtained by hydrodistillation with subsequent decantation). Results. A technological assessment of aromatic and bitter hop (2020–2023) was carried out using the experience of the «Elita Khmil» farm, and it was noted that these varieties had different biochemical compositions and brewing values. Differences were established in the absolute value of such indicators as the mass fraction of alpha and beta acids, essential oil, xanthohumol, and their composition. It was determined that the mass fraction of alpha acids in hop cones of finely aromatic varieties ranges from 3.2% in the Klon 18 variety to 5.6% in the Perlyna variety. In hop cones of the bitter group of varieties, this indicator ranged from 6.8% in the Promin variety to 9.5% in the Magnum variety. The content of beta acids in the studied varieties ranged from 4.3% (Klon 18) to 6.9% (Slovianka). The proportion of beta acids in the composition of bitter substances of the specified hop samples was equal to or exceeded the proportion of alpha acids. In aromatic and bitter varieties of Ukrainian selection, the amount of essential oil was 0.54–2.32 ml/100 g of dry hops, which indicated that Ukrainian varieties had a high-quality composition of bitter substances and essential oil. Conclusions. Expanding the range of hop products by forming highly productive hop plantations of promising varieties with certain characteristics will ensure a sufficient level of competitiveness of Ukrainian hop products on the world market.

Goal. To determine the brewing quality of hop granules of type 90 of Ukrainian production and to establish their competitiveness based on biochemical and technological assessments. Methods. Physico-chemical — to determine the quality indicators of hop granules, special and generally accepted in the hop industry, mathematical-statistical and methods of the European Brewing Convention, in particular, high-performance liquid chromatography, capillary gas chromatography, conductometry, spectrophotometry. Results. Biochemical evaluation of hop granules of type 90 of Ukrainian varieties Klon 18, Zlato Polissia, and Alta by the amount and composition of bitter substances, essential oil is given and their comparison with foreign granules of varieties Zhatetskyi (Czech Republic) and Magnum (Germany) is carried out. It was noted that the content of alpha acids in hop granules of aromatic varieties varied from 3.7% in the Klon 18 variety to 4.5% in the Zhatetskyi variety. The content of beta acids in the investigated granules ranged from 4.4% (Zlato Polissia) to 6% in the granules of the Zhatetskyi variety. The proportion of beta acids in the resins of the Klon 18, Zlato Polissia, and Zhatetskyi granules was significantly higher than the proportion of alpha acids, i.e. they retained a positive aromaticity ratio between the content of beta and alpha acids, which was 1.16–1.30. In the granules of fine aromatic varieties, the content of cohumulone was 24.6–26.0%. In hop granules of bitter varieties, the content of alpha acids varied from 9.7% in the Alta variety to 16.0% in the Magnum variety. The content of beta acids in these same granules ranged from 5.5% in the Alta variety to 7% in the Magnum variety. The content of cohumulone varied in the range from 23.5% in the granules of the Alta variety to 29% in the granules of the Magnum variety. It was proven that Ukrainian-made hop granules corresponded to world analogs in terms of their characteristics. Conclusions. It was established that the analyzed hop granules of type 90 of Ukrainian production were not inferior in quality to foreign granules and had the prospect of wide use in brewing, ensuring high-quality beer.

Goal. To form scientific-methodical approaches to evaluating the quality of hop of aromatic and bitter varieties according to biochemical and technological criteria regarding their suitability for use in various industries, in particular in brewing, baking, pharmacology, etc. Methods. Monographic — to study existing positive experiences on the specified issues; analysis and synthesis — for studying the results of research, generalization, systematization, comparison, and formation of conclusions; graphic — for data visualization and illustration of the studied phenomena. Modern physicochemical methods for determining biochemical indicators of the quality of hop and hop production were also used, such as high-performance liquid chromatography — to determine the amount and composition of bitter substances; conductometry — to determine the mass fraction of alpha acids; capillary gas chromatography — to determine the amount of essential oil and its components; the oxidation index of hop bitter substances was determined by spectrophotometry. Results. The analysis of the data obtained by domestic and foreign scientists and the results of the authors’ research confirmed the wide spectrum and high level of biological activity of hop compounds, which indicated the prospects of its use in many industries. To expand the field of application of the culture, scientific-methodical approaches to the comprehensive assessment of the quality of hop production of aromatic and bitter varieties were formed. It is primarily about the determination of organoleptic, biochemical economic-technological indicators, as well as the evaluation of the content of biologically active substances, and the analysis of therapeutic and preventive properties necessary for the use of the researched varieties in pharmaceuticals and medicine. This approach made it possible to scientifically substantiate the suitability of hops of breeding varieties for use in accordance with the purpose of the target product, as well as to develop biochemical and technological criteria for assessing its quality. The proposed evaluation methodology included methods for determining the brewing qualities of hops and their processing products, which were harmonized with the hop production analysis methods of the European Brewing Convention. Conclusions. The obtained results make it possible to assess the quality of hop and hop products following European standards, expand the scope of their use, and position Ukrainian culture varieties on the domestic and foreign markets. That may contribute to the development of the hop industry in general.

With the development of new trends in healthy eating, for consumer satisfaction, with aim to expand the range of bakery products and enrich bread with biologically active compounds of hops, bread production with the addition of cones of this unique plant in terms of bitter and polyphenolic substances, aromatic and essential oils has become widespread. The research conducted to study and substantiate the effective utilization of a complex of technologically valuable substances of Ukrainian fine aromatic hops of the Perlyna variety allowed to establish the possibility and feasibility of its application in baking and its impact on bread quality. The analysis of the results showed that the bittering qualities of hops had a significant impact on the taste of bread. In contrast, polyphenolic substances had a lesser effect on the taste, but in combination with bitter substances, they significantly affect consumer qualities. The results of studies of the application of sourdough starter of Perlyna aromatic hop with different content of alpha acids and polyphenolic substances showed that the bread had high taste qualities when added to the 1 kg of flour: 23.9 to 35.8 mg of bitter substances and 45.2 to 72.1 mg of polyphenolic substances. With lower amounts of bitter substances and higher amounts of polyphenols, the taste of the bread was almost the same as the control sample, although the physicochemical parameters improved. With an increase from 35.8 to 43.4 mg of bitter substances, a subtle bitterness was felt against the background of a pleasant hop aroma. Adding more than 50.8 mg of bitter substances to the 1 kg of flour made the bread noticeably bitter. Based on the example of the Pearl hop variety, the dosage of hop expenses was optimized and the calculation of the rate in baking was proposed, taking into account the content of bitter alpha acids in it. The optimally justified rate of bitter substances of hops to ensure excellent taste and consumer properties of bread is the range of added alpha acids from 23.9 to 43.4 mg per 1 kg of flour. The proposed technology has improved the consumer properties and taste of bakery products by imparting a hop aroma and a stable optimally normalized bread taste with a light, delicate bitterness. At the same time, the volume of bread, porosity, porosity structure and elasticity of the crumb are increased. Reducing the amount of yeast did not affect the fermentation of the dough and the stability of the shape of the final product. This will contribute to the health and preventive effects of the products.

Significant influence of weather conditions on alpha acid contents in hop cones is generally accepted. Long-term monitoring of alpha acid content in hops cultivated in the region of central Europe shows notable year to year differences. Mathematical models of the relationship between alpha acid content and meteorological parameters were worked out for 'Saaz' aroma variety using data covering the years 1981-2006. Mean alpha acid content was determined by lead conductance method (EBC 7.4, toluol). Meteorological data were provided with CHMI (Czech Hydrometeorological Institute) observatory in Doksany located approximately 2 km from the farm. Using multi-linear regression, a ten parameter model has been outlined. Average temperatures from July and August, average air humidity from June, July and August, average daily sunshine duration from June, July and August and accumulated precipitation from August have been found as key input variables of the model. Correlation coefficient of the relationship between predicted and actual alpha acid contents is r=0.914, coefficient of determinancy r 2 =0.835. The model showes that alpha acid content in 'Saaz' aroma hops is influenced by weather conditions in a relatively short time period June-August, i.e. stage of flowering, cone forming and ripening. July temperatures are the most significant weather parameter (r i =-0,24) effecting alpha acid contents in 'Saaz' hops confirming empiric experience.

Czech bitter varieties were evaluated between 2010 and 2022. Hop varieties displayed an average content of alpha acids between 10.24% w/w (Agnus) and 13.73% w/w (Gaia). Variability below 15%, proved good stability of alpha acids content in all tested bittering hops. All varieties showed a decrease in the content of alpha acids over a period of 13 years of hop cultivation. The highest content of beta acids was determined in Gaia (7.30% w/w). In contrast, the lowest content of beta acids was found in Rubín (3.73% w/w). The new bitter genotypes Uran and 5304 had an average alpha acid content of 11.56% w/w and 10.82% w/w, respectively. Uran showed an average beta acid content of 5.47% w/w and for the genotype 5304 it was 3.61% w/w. In terms of the alpha/beta acids ratio, the hop varieties can be divided into three groups. The first group included the varieties with an alpha/beta acids ratio below 2, i.e. Vital, Boomerang and Gaia. While Agnus and Uran displayed an alpha/beta ratio slightly above 2. The highest alpha/beta ratio above 3 was found in Rubín and the 5303 genotype.

The brewing qualities of hop raw materials are critical in the selection of varieties for beer production. The accumulation of bitter substances, polyphenolic substances and essential oil in hop cones depends on the variety and weather conditions. In this regard, the aim of our research was to scientifically substantiate the proportion of influence of stressful weather factors and varietal characteristics on the process of forming the brewing qualities of hop cones during 2012–2022. For the study, hop cones of 9 varieties of aromatic and bitter types were selected, which were grown in the conditions of hop enterprises in the Zhytomyr region of Ukraine. It was found that in terms of bitter substances content and their variability, the most perspective from the technological point of view were Zagrava (23.0%) and Ruslan (26.1%) varieties with Vp = 8.0–11.7%. The maximum values of alpha-acid content were observed in the same varieties – 5.7% and 9.2%, respectively, with low and medium variability over the years of research (Vp = 8.7–14.0%). The highest stability in the content of polyphenolic substances (Vp = 6.4–8.3%) was found in the varieties Zlato Polissya and Ruslan. The content of essential oil was characterized by high variability (Vp up to 49.4%), the most stable were the varieties Zlato Polissya (Vp = 17.0%) and Ruslan (Vp = 22.8%). It was established that during the study period, the dominant influence on the content of bitter substances, alpha acids and essential oil was exerted by the variety (up to 69.1%), while the content of polyphenolic substances in aromatic hops was determined by weather conditions (34.3%). The results highlight the importance of varietal characteristics in the stability of the biochemical composition of hops in a changing climate. The results are of practical importance for growers and brewers, as well as for hop breeding. Resistant varieties are highly to be used more as a starting material for the creation of new hop varieties that will be more resistant to climate change and provide more stable indicators of brewing qualities of hops.

This study quantifies the effects of weather conditions, irrigation, and plant age on yield and alpha-acids content of Czech hop cultivars Saaz, Sládek, Premiant and Agnus in a 25-year long period, i.e., from 1993 to 2018. The yields of Czech hop cultivars were increasing for the first three years of plant age until they stabilized and then started to decline slightly for 15 to 20 years until they reached the optimal time for replanting. The highest alpha-acids content in hop cones was achieved in the first year of cultivation, followed by a logarithmic decline in the upcoming years. Rainfall was the most significant factor that positively influenced the yield of Saaz hops with correlations of r = 0.59 and 0.61 (P < 0.01) for total seasonal rainfall (April–August), 0.65 (P < 0.001) and 0.60 (P < 0.01) for daily rainfall above 3 mm, 0.37 (P < 0.05) and 0.58 (P < 0.01) for rainfall in May and 0.50 (P < 0.01) and 0.32 (P < 0.05) in July in the Saaz region and the Stekník farm, respectively. The yield of cultivars Sládek, Premiant and Agnus was not statistically influenced by the amount of precipitation, but there was a positive effect of irrigation level on yield increase with correlations 0.58 (P < 0.01), 0.55 and 0.49 (P < 0.05), respectively. High air temperatures during summer were the most significant factor that negatively influenced the alpha-acids content with the correlations ranging from –0.56 to –0.83. However, cv. Agnus showed a stable weather-independent alpha-acids content.

Population development of Phorodon humuli and predators ( Orius spp.) within hop cones: Influence of aphid density on hop quality

Hop pellets type 90 are the most frequent hop products used in brewing. They are usually manufactured by drying hop cones, temporary storage of dry and pressed cones, milling and pelletising. Other possibility is a complete integration of hop harvest, cone drying, milling and pelletising in continuous process without temporary storage of pressed cones. The paper deals with the losses of bitter substances (primary α-acids) during hop cones drying, their pelletisation by two manufacturing procedures and storage in different conditions. The results of this study show that integrated procedure of hop pelletising decreases the total loss of α-acids compared to the usual procedure. During storage of hop pellets (produced by integrated procedure) the highest decrease (loss) of α-acids content was observed in pellets stored at 21 °C in the presence of air and the lowest under inert atmosphere (N 2 ) at 4 to 7 °C, respectively.

The abundance, diversity and temporal fluctuations in plant‐parasitic nematodes associated with hop production, and their effect on cone yield and levels of alpha acids were assessed in two hop (cv. ‘Pride of Ringwood’) gardens in Tasmania, Australia within the 1999/2000 season at Forrester River, and within the 2001/2002 season at Gunns Plains. The most abundant plant‐parasitic nematode found at both sites was Heterodera humuli Filipjev 1934. Heliocotylenchus dihystera, Pratylenchus spp. and Meloidogyne spp. were present in comparatively low numbers. Temporal fluctuations in the numbers of H. humuli suggested that one generation occurred at Forrester River and Gunns Plains. At Forrester River, the numbers of H. humuli second stage juveniles (J2) on 11 October 1999 were significantly negatively correlated with cone yield on 17 March 2000. No significant correlations were detected between numbers of H. humuli J2 and cone yield at later dates, or between numbers of H. humuli J2 at any sampling date and alpha acid content.

Evaluation of the stability of hop pellets subjected to different storage conditions during three years

Introduction. According to the data of foreign studies, prenyl fl avonoids and bitter substances of hop have signifi cant antioxidant, antiviral, antimicrobial, anti-infl ammatory and anti-carcinogenic properties. Methods. A complex of the following methods was used: a monographic method, analysis, synthesis and comparison, mathematical-statistical and modern physical-chemical methods of determining qualitative indices of hop, special and common in hop-growing industry, which allowed obtaining scientifi cally valid results. Results. The modern level of knowledge about biologically active compounds of hop and their properties was analyzed, in particular, bitter substances and xanthohumol. The quantitative and qualitative content of bitter substances, essential oil and xanthohumol in hop varieties of Ukrainian, European and American breeding was studied. Among the Ukrainian varieties, the highest amount of xanthohumol was found in Ruslan and Xanthus varie- ties – 1.16 % and 1.06 % against dry substances respectively, and its minimal amount was detected in the cones of the bitter Alta variety. Among the European varieties, the highest amount of this substance is contained in the German variety HallertauerTaurus – 0.9–1.0 %, up to 1 % in the Czech variety Agnus and the English va- riety Admiral, with the content of 0.95 %–1.09 %. There is a strong correlation between the accumulation of xanthohumol and alpha acids in the formation and ripening of the cones. The maximal amount of xanthohumol is formed in the hop cones in the phase of complete technical ripeness. The content of this substance in hop cones depends on the breeding variety and is a varietal trait, genetically fi xed for each variety. The quantitative amount of xanthohumol may be one of biochemical criteria of identifying the variety. Conclusions. By their characteristics, the Ukrainian hop varieties correspond to the world’s analogues, namely, according to their bio- chemical and technological indices, hop varieties Klon-18 and Zlato Polissia correspond to the characteristics of the hop of the Czech Saaz variety, the biochemical indices of the bitter Alta variety correspond to the Ger- man variety Magnum, and such varieties as Slovianka and Zahrava exceed the world’s analogues considerably in the composition and quality of bitter substances and essential oils and are unique.

The analysis and comparative description are carried out of varieties of brewing barley light malt and type 90 hops from domestic and foreign producers, as the main plant raw material that forms the quality of beer. The quality indexes of malt samples and hop pellets have been tested for compliance with applicable standards.The obtained results indicate that the varieties of barley malt are homogeneous grain mass, do not contain moldy and damaged grains, weed impurities, have a color from light yellow to gray to yellow. Ten samples of malt of various grades for beer production have been studied in terms of mass fraction of moisture (3.2–3.7%), mass fraction of extract in dry matter of fine malt (82.4–87.5%), degree (0 9–1.2%), the mass fraction of protein substances in dry matter of malt (9.1–10.1%), the Kolbach index (39.1–40.2%), the amount of nitrogenous substances (0.70–0, 74%). It has been established that the quantitative content of β-glucans significantly differs in different varieties: the minimum amount is contained in the malt Château Wien, the maximum is Pilsner Weyermann and Munich.According to the research results, it has been established that barley malt varieties have a pronounced malt aroma and sufficient fermentative activity and can serve as the base in the mash in the production of beer. It is proved that malt samples have an acceptable amount of toxic substances and radionuclides that will not affect the quality of the finished product. In assessing the quality of varieties of hop pellets by organoleptic indicators, the mass fraction of moisture and α-acids, it is established that the samples have the values of the indicators within the permissible limits. The samples have a cylindrical shape of different hues and approximately the same size; pure hop aroma, without an off-aroma; the color on the surface and at the boundary of the pellets meets the requirements of the standard. The mass fraction of α-acids is in the range from 3.0 to 12.7 %. It is revealed that bitter and aromatic hops are used for pellet production. The samples Magnym and Hallertau Perle are classified as bitter varieties. Hop pellets of the varieties Premiant and Sladek are bitter and aromatic.According to the results of the determination of quality indicators, the following ones have been identified as the best: malt – Munich, Pilsner, Carabohemian, hop pellets – Bramling Cross, Mandarina Bavaria and Magnym. The proposed varieties of malt and hops allow obtaining beer with high organoleptic characteristics, colloidal stability and expand the range of the industry by creating new varieties to meet the needs of the consumer.