Beer Polyphenols—Bitterness, Astringency, and Off-Flavors

Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer

Mousy off-flavor describes N-heterocycles compounds related to spoilage in the brewing industry. It has also been identified in sour beers through sensory analysis. Therefore, preventing spoilage N-heterocycles development is essential to preserve end-products and obviate economic losses. To this day, no methods or protocols have been reported to identifying mousy off-flavor compounds in a beer matrix. The main objective of this work was to develop a standardized quantification method for 2-acetyl-3,4,5,6-tetrahydropyridine (ATHP) in beer matrix, by Liquid Chromatography Mass Spectrometry with Electrospray Ionization (LC-MS-ESI). Extraction of ATHP in the samples was performed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique. Over a dozen different potentially mousy cask-aged sour beers including other spontaneously fermented beverages were provided, based on sensory analysis, to determine the variation in ATHP levels. Results indicated ATHP was found in all the samples, ranging from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1. Herein, we described our detection method of mousy-off flavor compounds which enables future research to mitigate the occurrence of such defects in fermented beverages matrix.•ATHP content in samples varied from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1.•The recovery range of ATHP using LC-MS-ESI varied from 71% to 97%.•Basified QuEChERS salting-out procedure is applicable for ATHP extraction from beer and other fermented beverages matrices.

A Review of N-Heterocycles: Mousy Off-Flavor in Sour Beer

Beer has over 600 flavor compounds and creates a positive tasting experience with acceptable sensory properties, which are essential for the best consumer experience. Spontaneous and mixed-culture fermentation beers, generally classified as sour beers, are gaining popularity compared to typical lager or ale styles, which have dominated in the USA for the last few decades. Unique and acceptable flavor compounds characterize sour beers, but some unfavorable aspects appear in conjunction. One such unfavorable flavor is called "mousy". This description is usually labeled as an unpleasant odor, identifying spoilage of fermented food and beverages. It is related as having the odor of mouse urine, cereal, corn tortilla chips, or freshly baked sour bread. The main compounds responsible for it are N-heterocyclic compounds: 2-acetyltetrahydropyridine, 2-acetyl-1-pyrroline, and 2-ethyltetrahydropyridine. The most common beverages associated with mousy off-flavor are identified in wines, sour beers, other grain-based beverages, and kombucha, which may contain heterofermentative lactic acid bacteria, acetic acid bacteria, and/or yeast/fungus cultures. In particular, the fungal species Brettanomyces bruxellensis are associated with mousy-off flavor occurrence in fermented beverages matrices. However, many factors for N-heterocycle formation are not well-understood. Currently, the research and development of mixed-cultured beer and non/low alcohol beverages (NABLAB) has increased to obtain the highest quality, sensory, functionality, and most notably safety standards, and also to meet consumers' demand for a balanced sourness in these beverages. This paper introduces mousy off-flavor expression in beers and beverages, which occurs in spontaneous or mixed-culture fermentations, with a focus on sour beers due to common inconsistency aspects in fermentation. We discuss and suggest possible pathways of mousy off-flavor development in the beer matrix, which also apply to other fermented beverages, including non/low alcohol drinks, e.g., kombucha and low/nonalcohol beers. Some precautions and modifications may prevent the occurrence of these off-flavor compounds in the beverage matrix: improving raw material quality, adjusting brewing processes, and using specific strains of yeast and bacteria that are less likely to produce the off-flavor. Conceivably, it is clear that spontaneous and mixed culture fermentation is gaining popularity in industrial, craft, and home brewing. The review discusses important elements to identify and understand metabolic pathways, following the prevention of spoilage targeted to off-flavor compounds development in beers and NABLABs.

Identification of Compounds That Impact Consumer Flavor Liking of American-European Hazelnut Hybrids Using Nontargeted LC/MS Analysis

American-European (Corylus americana × Corylus avellana) hazelnut hybrids are being developed for the Midwest-growing region of the United States. However, an inadequate understanding of the compounds that impact the consumer acceptance of hazelnuts limits breeding programs. Nontargeted liquid chromatography/mass spectrometry (LC/MS) chemical profiles of 12 roasted hybrid hazelnut samples and the corresponding consumer flavor liking scores were modeled by orthogonal partial least squares with good fit and predictive ability (R2Y > 0.9, Q2 > 0.9) to identify compounds that impact nut liking. The five most predictive compounds (1-5) were negatively correlated to flavor liking, selected as putative markers, purified by multidimensional preparative LC/MS, structurally elucidated (nuclear magnetic resonance, MS), quantified, and validated for sensory relevance. Compound 1 was identified as 1″-O-3'-b-glucofuranosyl-1'-O-1-b-glucofuranosyl-(2,6-dihydroxyphenyl)-ethan-4-one. Compounds 2 and 4 were identified as rotamers of 2-(3-hydroxy-2-oxoindolin-3-yl) acetic acid 3-O-6'-galactopyranosyl-2″-(2″oxoindolin-3″yl) acetate, whereas compounds 3 and 5 were identified as rotamers of 1″-O-1'-b-glucofuranosyl-9-O-6'-b-glucopyranosyl-2″-(2″-oxoindolin-3″yl) acetate. Sensory evaluation determined that all compounds were characterized by bitterness and/or astringency. The sensory threshold values of compounds 1-5 were determined to be below the concentrations reported in 91, 83, 41, 25, and 41% of all 12 hybrid hazelnut samples, respectively, indicating they contributed to aversive flavor attributes.

UHPLC-PAD Protocol for the Simultaneous Identification of Polyphenols and Bitter Acids: Organoleptic and Nutraceutical Fingerprinting of Bergamot-Flavored Craft Beer

In this study, a UHPLC-PDA method for the simultaneous identification of polyphenols and bitter acids (alpha, beta, and isoalpha) in beer was developed. The resulting chemical profiles were leveraged to distinguish the characteristics of four (IPA, Lager, Blanche, ALE) bergamot-flavored beers, produced on a pilot-scale plant. In a streamlined 29 min analysis, thirty polyphenols and fourteen bitter acids were successfully identified under optimized separation conditions. Validation, encompassing parameters such as LOD (from 0.028 ppm for isorhamnetin to 0.106 for narirutin), LOQ (from 0.077 ppm for naringenin to 0.355 for narirutin), R2 (always more than 0.9992), repeatability (from 0.67% for tangeretin to 6.38% for myricetin), and reproducibility (from 0.99% for sinensetin to 6% for naringin), was conducted for polyphenol quantification using constructed calibration curves with seven levels. Exploring polyphenolic components as potential discriminators among different beer styles, a total of thirty-two polyphenolic compounds were identified and quantified, including characteristic bergamot peel polyphenols like neoeriocitrin (from 7.85 ppm for CBS2 to 11.95 ppm in CBS1); naringin (from 4.56 ppm for CBS4 to 10.96 in CBS1), and neohesperidin (from 5.93 in CBS3 to 15.95 for CBS2). The multivariate analysis provided additional insights into variations among specific beer styles, revealing discrepancies in the presence or relative concentrations of specific compounds linked to brewing ingredients and processes. This research enhances the fingerprinting of the chemistry governing beer quality through a straightforward and cost-effective analytical approach.

Development of gluten-free craft beer: Impact of brewing process on quality attributes and consumer expectations for sensory properties

To date, few studies investigated the differences between the two main gluten-free (GF) brewing techniques, such as the use of enzymes and the use of unconventional GF grains in brewing, by consumer perspective. In this study a GF beer brewed with sorghum and quinoa, as brewing adjuncts, was compared to the enzymatic-treated counterpart, in order to evaluate the effect of deglutinization treatment on physicochemical, volatile, and sensory characteristics of final beer. Moreover, the influence of brewing process and raw materials information on consumers' sensory perceptions, willingness to buy (WTB) and willingness to pay (WTP) was also investigated (n = 105 consumers), under blind (B), expected (E), and informed (I) conditions. The enzymatic-treated sample showed comparable physicochemical attributes with the untreated counterpart, except for a significant reduction in color and foam stability (p < 0.05). Non-significant difference between samples was found in the overall liking, WTB, and WTP mean scores in all three sensory test conditions (p > 0.05). The information about the deglutinization treatment had a negative impact on overall liking (p < 0.01), although WTP for both samples was significantly higher in the informed test than in blind condition (p < 0.05). Overall, Check-All-That-Apply test results confirmed that the deglutinization treatment does not affect the beer sensory profile, even if the information about brewing ingredients and technologies may slightly influence the consumers' sensory perception. Therefore, this result proves that it is possible to produce a marketable GF beer, simply by partially replacing 40% of barley malt with unconventional GF grains, without using enzymes for gluten reduction purpose.

Current strategies for the management of valuable compounds from hops waste for a circular economy

World beer production generates large volumes of waste discharged with every brew. Recently, new methods of reducing and reusing hops waste: hot trub (HT), and brewer-spent hops (BSH) are being exploited to improve the circular economy processes. This review outlines the current achievements in the management of hops waste. Following an in-depth review of various scientific publications, current strategies are discussed as a sustainable alternative to food waste exploitation and an inexpensive source of valuable compounds. Moreover, key aspects concerning the nutritional value of hops waste and the potential to enhance the functional properties of food and beverages are highlighted. Due to their nutritional composition, hops residues may be used as prospective sources of added-value co-products or additives for food enrichment, especially for products rich in fat, or as a new source of vegetable protein.

Identification of nonvolatile chemical constituents in Chinese Huangjiu using widely targeted metabolomics

Huangjiu is a traditional Chinese alcoholic beverage, whose non-volatile chemical profile remains unclarified. Here, the non-volatile compounds of Huangjiu were first identified using a widely targeted metabolomics analysis. In total, 1146 compounds were identified, 997 of them were identified in Huangjiu for the first time. Moreover, 113 compounds were identified as key active ingredients of traditional Chinese medicines and 78 components were found as active pharmaceutical ingredients against 389 diseases. In addition, the comparative analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that Huangjiu from different regions differ in metabolite composition. Cofactor and amino acid biosynthesis and ABC transport were the dominant metabolic pathways. Furthermore, 7 metabolic pathways and 77 metabolic pathway regulatory markers were further found to be related with the different characteristics of different Huangjius. This study provides a theoretical and material basis for the quality control, health efficacy, and industrial development of Huangjiu.

Effects of Dry-Hopping on Beer Chemistry and Sensory Properties-A Review

Dry-hopping is the addition of hops to the wort on the cold side of the brewing process. Unlike standard hop additions, its main purpose is not to produce a characteristic bitterness but to extract as much of the hop essential oils as possible, which are largely lost in the standard hopping process. When dry-hopped, it is possible to obtain a beer with an aroma that is difficult to achieve when hops are used on the hot side of the brewing process. As a result, this process has become very popular in recent years, particularly in beers that belong to the 'craft beer revolution' trend. In addition, the usefulness of this process is increasing with the development of new hop varieties with unique aromas. This article presents the main components of hops, focusing on those extracted during the process. Changes in the composition of beer bittering compounds and essential oils resulting from this process are discussed. This paper presents the current state of the knowledge on the factors affecting the degree of extraction, such as hop dosage, the time, and temperature of the process. Issues such as process-related physicochemical changes, hop creep, low flavor stability, haze formation, and green flavor are also discussed.

Ultrasonication-assisted enzymatic bioprocessing as a green method for valorizing oat hulls

Ultrasonication-assisted enzymatic treatments using Viscozyme®, Alcalase®, and feruloyl esterase were applied to recover proteins, avenanthramides, phenolic acids, free sugars, and organic acids from oat hulls (OH). The profiles of the chemical compounds in OH were markedly influenced by the nature of enzymes, ultrasonication frequency, and processing time. A significant increase in the contents of proteins and phenolic acids was observed in the liquid fraction of all enzymatic treatments, which was 2-19 folds higher than those detected in untreated OH. In contrast, avenanthramides were mostly degraded during enzyme hydrolyses. The highest content of proteins (68.9 g/100 g DM) was found in the liquid fraction after the feruloyl esterase treatment assisted with 90 min of ultrasonication at 25 kHz. This fraction also contained 0.07% phenolic acids, 14.1% free sugars, and 1.8% organic acids, which can be potentially used as the ingredient of novel food products.

Chemo-preventive effects and antitumorigenic mechanisms of beer and nonalcoholic beer toward 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) - induced lung tumorigenesis in A/J mice

We investigated the chemopreventive effects of beer, nonalcoholic beers (NABs), and beer-components (glycine betaine (GB)) on NNK-induced lung tumorigenesis in A/J mice, and the possible mechanisms underlying the antitumorigenic effects of beer, NABs, and beer-components. Beer, NABs, and GB reduced NNK-induced lung tumorigenesis. We investigated the antimutagenicity of beer, NABs and beer-components (GB and pseudouridine (PU)) toward the mutagenicity of 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Beer, NABs, and beer components were antimutagenic toward MNNG and NNK in the Ames test using S. typhimurium TA1535. In contrast, MNNG and NNK mutagenicity detected in S. typhimurium YG7108, a strain lacking O⁶-methylguanine DNA methyltransferases (ogt_ST and ada_ST) did not decrease in the presence of beer, NABs, or beer components, suggesting that they may mediate its antimutagenic effect by enhancing DNA damage repair. Phosphorylation of Akt and STAT3, with or without epidermal growth factor stimulation, in lung epithelial-like A549 cells were significantly decreased following beer, NABs, GB and PU. They targeted both the initiation and growth/progression steps of carcinogenesis, specifically via antimutagenesis, stimulation of alkyl DNA-adduct repair, and suppression of Akt- and STAT3- mediated growth signaling. GB and PU may contribute, in part, to the biological effects of beer and NABs via the suppression of Akt and STAT3 phosphorylation.

Impact of the Addition of Fruits of Kamchatka Berries (L. caerulea var. kamtschatica) and Haskap (L. caerulea var. emphyllocalyx) on the Physicochemical Properties, Polyphenolic Content, Antioxidant Activity and Sensory Evaluation Craft Wheat Beers

Kamchatka berry (Lonicera caerulea var. kamtschatica) and haskap (Lonicera caerulea var. emphyllocalyx) fruit are important sources of bioactive compounds, mainly polyphenols, but also macro- and microelements. Physico-chemical analysis showed that wheat beers with added fruit were characterised by an average 14.06% higher ethanol content, lower bitterness and intense colour compared to the control, which was a wheat beer without added fruit. Wheat beers enriched with kamchatka berry fruit, including the "Aurora" variety, had the highest polyphenolic profile (e.g., chlorogenic acid content averaged 7.30 mg/L), and the antioxidant activity of fruit-enriched wheat beers determined by the DPPH method showed higher antioxidant activity of wheat beers enriched with kamchatka berry fruit, while those determined by the FRAP and ABTS methods showed higher antioxidant activity of wheat beers enriched with haskap fruit, including the "Willa" variety. Sensory evaluation of the beer product showed that wheat beers enriched with kamchatka berry fruits of the "Duet" variety and haskap fruits of the "Willa" variety were characterised by the most balanced taste and aroma. On the basis of the conducted research, it follows that both kamchatka berry fruits of the "Duet" and "Aurora" varieties and haskap fruit of the "Willa" variety can be used successfully in the production of fruity wheat beers.

Interactions between Beer Compounds and Human Salivary Proteins: Insights toward Astringency and Bitterness Perception

Beer is one of the most consumed beverages worldwide with unique organoleptic properties. Bitterness and astringency are well-known key features and, when perceived with high intensity, could lead to beer rejection. Most studies on beer astringency and bitterness use sensory assays and fail to study the molecular events that occur inside the oral cavity responsible for those perceptions. This work focused on deepening this knowledge based on the interaction of salivary proteins (SP) and beer phenolic compounds (PCs) and their effect toward these two sensory attributes. The astringency and bitterness of four different beers were assessed by a sensory panel and were coupled to the study of the SP changes and PC profile characterization of beers. The human SP content was measured before (basal) and after each beer intake using HPLC analysis. The beers’ PC content and profile were determined using Folin–Ciocalteu and LC-MS spectrometry, respectively. The results revealed a positive correlation between PCs and astringency and bitterness and a negative correlation between SP changes and these taste modalities. Overall, the results revealed that beers with higher PC content (AAL and IPA) are more astringent and bitter than beers with a lower PC content (HL and SBO). The correlation results suggested that an increase in whole SP content, under stimulation, should decrease astringency and bitterness perception. No correlation was found between the changes in specific families of SP and astringency and bitterness perception.

A Comprehensive Comparison of Gluten-Free Brewing Techniques: Differences in Gluten Reduction Ability, Analytical Attributes, and Hedonic Perception

This study provides a comprehensive comparison among the most common gluten-free (GF) brewing practices, with a focus on the impact of each treatment on physicochemical parameters and consumer acceptability of the final beer. In addition, the influence of a longer cold maturation on the natural reduction of the gluten content was investigated. Prolyl endopeptidase addition was found to be the most effective treatment in reducing gluten levels (−75.93%), followed by silica gel (−53.09%), longer cold maturation (−4.32%), and tannins (−1.85%). Nonetheless, none of the treated beer samples was gluten-free (gluten content > 20 ppm) due to the high nitrogen content of the original wort. The silica gel application treatment affected the physicochemical and sensory characteristics of the final beer the least. According to the difference from control test results, no significant difference in terms of overall liking, appearance, odor/aroma, or taste was observed between the silica gel-treated sample and control beer (p > 0.05). On the other hand, the application of enzymes and tannins significantly affected the appearance and the beer odor/aroma. Nevertheless, all beer samples received positive sensory acceptance scores.

Effect of the Addition of Lemongrass (Cymbopogon citratus) on the Quality and Microbiological Stability of Craft Wheat Beers

Lemongrass (Cymbopogon citratus) is a valuable source of vitamins, macro- and microelements, and essential oils. The purpose of this study was to compare the physicochemical properties, sensory properties, antioxidant activity, and microbiological stability of wheat beers enriched with varying additions of crushed lemongrass. Sensory evaluation showed that wheat beers enriched with 2.5% m/v lemongrass were characterised by balanced taste and aroma (overall impression). Physicochemical analysis of the wheat beers showed that increasing the concentration of lemongrass in the finished product negatively affected the ethanol content. Alcohol content in wheat beer enriched with 1% m/v lemongrass was on average 14.74% higher than wheat beer enriched with 2.5% m/v lemongrass and on average 17.93% higher than wheat beer enriched with 5% m/v addition of lemongrass. The concentration of lemongrass in the finished product also increased the acidity of the beers and affected the colour of the wheat beers compared to the control beer. The total polyphenol content and antioxidant activity of lemongrass-enriched wheat beers varied. Of the lemongrass-enriched beers analysed, the beer product with 5% m/v lemongrass was the most microbiologically stable. According to the study, crushed lemongrass-enriched wheat beer may represent a new trend in the brewing industry, but the brewing process still needs to be improved.

The Effect of the Addition of Ozonated and Non-Ozonated Fruits of the Saskatoon Berry (Amelanchier alnifolia Nutt.) on the Quality and Pro-Healthy Profile of Craft Wheat Beers

Research into the suitability of domestic raw materials, including, for example, new wheat cultivars and fruit additives for the production of flavoured beers, is increasingly being undertaken by minibreweries and craft breweries. The fruits of the Saskatoon berry are an important source of bioactive compounds, mainly polyphenols, but also macro- and microelements. The fruits of two Canadian cultivars of this species, 'Honeywood' and 'Thiessen', were used in this study. Physicochemical analysis showed that wheat beers with the addition of non-ozonated fruit were characterised by a higher ethanol content by 7.73% on average. On the other hand, enrichment of the beer product with fruit pulp obtained from the cv. 'Thiessen' had a positive effect on the degree of real attenuation and the polyphenol profile. Sensory evaluation of the beer product showed that wheat beers with the addition of 'Honeywood' fruit were characterised by the most balanced taste and aroma. On the basis of the conducted research, it can be concluded that fruits of both cvs. 'Honeywood' and 'Thiessen' can be used in the production of wheat beers, but the fermentation process has to be modified in order to obtain a higher yield of the fruit beer product.

Feasibility of Defatted Juice from Sea-Buckthorn Berries (Hippophae rhamnoides L.) as a Wheat Beer Enhancer

Juice made from sea-buckthorn berries (Hippophae rhamnoides L.) is a valuable source of bioactive compounds, vitamins, as well as micro- and macronutrients. By applying defatted sea-buckthorn juice, it is possible to enhance wheat beer and change its sensory properties and the contents of bioactive compounds in the finished product. A sensory assessment showed that wheat beers with a 5% v/v addition of sea-buckthorn juice were characterised by a balanced taste and aroma (overall impression). Physicochemical analyses showed that, compared to the control samples, wheat beers enhanced with defatted sea-buckthorn juice at a rate of 5% v/v or 10% v/v had high total acidity with respective mean values of 5.30 and 6.88 (0.1 M NaOH/100 mL), energy values lower on average by 4.04% and 8.35%, respective polyphenol contents of 274.1 mg GAE/L and 249.7 mg GAE/L, as well as higher antioxidant activity (measured using DPPH, FRAP, and ABTS assays). The findings show that the samples of wheat beer enhanced with sea-buckthorn juice had average ascorbic acid contents of 2.5 and 4.5 mg/100 mL (in samples with 5% v/v and 10% v/v additions, respectively) and contained flavone glycosides, e.g., kaempferol-3-O-glucuronide-7-O-hexoside. Based on the current findings, it can be concluded that wheat beer enhanced with sea-buckthorn juice could emerge as a new trend in the brewing industry.

Suitability of Selected Winter Cultivars of Wheat from Production of Wheat Beer

The study investigated the feasibility of three winter cultivars of wheat – Elixer, Rockefeller and Gimantis, for production of wheat beer. Reference samples were produced from commercially available wheat malt. The findings showed the beer produced from commercially available wheat malt presented the best sensory and physicochemical parameters, including real final fermentation of 70.11%. The results related to the investigated wheat cultivars showed good quality properties in the beer produced from malts obtained from Gimantis cultivar (content of CO2 – 0.58%), and from Rockefeller cultivar (alcohol content - 4.62% v/v). A similar relationship was observed in the sensory assessment. The findings related to beer produced from malt of Elixer wheat cultivar showed relatively low effectiveness of the production process (69.7%) and final beer fermentation (65.52%), and at the same time high contents of polyphenols (210 mg/dm3) and antioxidant activity. Wheat malts produced from Gimantis and Rockefeller cultivars can effectively be used as a raw material in beer production; on the other hand, malt from Elixer cultivar, found with higher antioxidant contents, may be used as an additive to be applied in a small quantity in the mashing process in order to enhance the beer in terms of its potential health benefits.

Quality and Pro-Healthy Properties of Belgian Witbier-Style Beers Relative to the Cultivar of Winter Wheat and Raw Materials Used

Unmalted wheat grain and barley malt are the basic materials used in the production of Belgian wheat beers known as Witbier. A change in the ingredients defined in the recipe, by which part of the unmalted wheat is replaced with wheat malt, can positively affect the quality of the beverage produced. The purpose of the study was to brew Witbier-style beers made from four cultivars of winter wheat, with a 50% share of unmalted wheat and barley malt as well as Witbier-style beers made from four wheat cultivars, where 25% of unmalted wheat was replaced with wheat malt. Physicochemical and sensory analyzes showed mild differences in the quality of the beer products, more specifically higher alcohol content (by 11.33%) were found in beers made without the addition of wheat malt, while higher sensory attractiveness and 17.13% higher total polyphenol content were identified in beers enhanced with wheat malt. Phenolic compounds were identified using UPLC-PDA-MS/MS. The highest flavanol content, including kaempferol 3-O-rhamnoside-7-O-pentoside, was found in beers produced using wheat grains of the ‘Elixer’ cultivar, whether or not wheat malt was added; the values were 1.31 mg/L in E50 beer, and 1.39 mg/L in E25 beer. The same beer samples with the highest antioxidant and antiradical activity were found (in E25 beer, 2.35 mmol TE/L, and in E50 beer, 2.12 mmol Fe^2+/L). The present findings show that the investigated wheat cultivars may be used in beer production, whereas replacing part of unmalted wheat with wheat malt can improve the sensory profile of the beer produced.

The Effect of Dry Hopping Efficiency on β-Myrcene Dissolution into Beer

The production of heavily hopped beers, such as Indian Pale Ale (IPA) styles, has been gaining momentum in recent years in the Central European markets. To this end, the dry hopping process is becoming increasingly popular, mostly in microbreweries, but also with larger manufacturers. In our research, we investigated the dissolution rate of the main volatile component of hops, β-myrcene with a modified dry hopping method. Following the primary fermentation, we applied the dry hopping process, where the weighed hops were chopped and blended into a container with 0.5 L of beer and later added to the young beer. During the dry hopping process, we determined various important parameters of the beer, and we repeated the same measurements for the bottled beer. In the first 96 h of the dry hopping process, we monitored the concentration of β-myrcene so that we managed to determine the dissolution rate constant (k = 0.1946 h^-1). The β-myrcene concentration stabilizes after 44 h in the fermenter. At the same time, measurements were conducted for bitterness, pH, CO₂ and alcohol content, extract and density during the process. Our experiment demonstrates that a new method of dry hopping provides a much higher concentration of β-myrcene (215 μg/L) than other methods indicated in former studies in the field. A health and safety assessment of β-myrcene was also made and we determined what the safe amount of β-myrcene ingested with IPA beer is. Our modified process was successful, we were able to determine the dissolution rate of β-myrcene, and the recommended daily intake of IPA beer with particular reference to β-myrcene.

Effect of Ozone-Treated or Untreated Saskatoon Fruits (Amelanchier alnifolia Nutt.) Applied as an Additive on the Quality and Antioxidant Activity of Fruit Beers

Fruit of Saskatoon (Amelanchier alnifolia Nutt.) are a good source of bioactive compounds, such as polyphenols, including anthocyanins, as well as vitamins, macro- and microelements and fibre. By treating Saskatoon fruits with gaseous ozone, and adding the material as an enhancer to barley beers, it is possible to impact the contents of bioactive compounds in the produced fruit beers. Sensory tests showed that beers made from barley with addition of Saskatoon fruit of the ‘Smoky’ cultivar were characterised by the most balanced taste and aroma. Physicochemical analyses of fruit beers, produced with Saskatoon fruit pulp added on the seventh day of fermentation, showed that the beers enhanced with ozone-treated and untreated ‘Smoky’ Saskatoon fruits had the highest contents of alcohol, 5.51% v/v and 5.66% v/v, respectively, as well as total polyphenol contents of 395 mg GAE/L and 401 mg GAE/L, respectively, and higher antioxidant activity (assessed using DPPH^•, FRAP and ABTS^+• assays). It was demonstrated that the ozonation process led to a decrease in the contents of neochlorogenic acid, on average by 91.00%, and of caffeic acid by 20.62%, relative to the beers enhanced with ‘Smoky’ Saskatoon fruits not subjected to ozone treatment. The present study shows that Saskatoon fruits can be used in the production of beer, and the Canadian cultivar ‘Smoky’ is recommended for this purpose.

The Influence of Hop Phenolic Compounds on Dry Hopping Beer Quality

Background: The article considers the phenolic hop compounds’ effect on the quality indicators of finished beer. The topic under consideration is relevant since it touches on the beer matrix colloidal stability when compounds with potential destabilizing activity are introduced into it from the outside. Methods: The industrial beer samples’ quality was assessed by industry-accepted methods and using instrumental analysis methods (high-performance liquid chromatography methods—HPLC). The obtained statistical data were processed by the Statistics program (Microsoft Corporation, Redmond, WA, USA, 2006). Results: The study made it possible to make assumptions about the functional dependence of the iso-α-bitter resins and isoxanthohumol content in beer samples. Mathematical analysis indicate interactions between protein molecules and different malted grain and hop compounds are involved in beer structure, in contrast to dry hopped beer, where iso-a-bitter resins, protein, and coloring compounds were significant, with a lower coefficient of determination. The main role of rutin in the descriptor hop bitterness has been established in kettle beer hopping technology, and catechin in dry beer hopping technology, respectively. The important role of soluble nitrogen and β-glucan dextrins in the perception of sensory descriptors of various technologies’ beers, as well as phenolic compounds in relation to the formation of bitterness and astringency of beer of classical technology and cold hopping, has been shown. Conclusions: The obtained mathematical relationships allow predicting the resulting beer quality and also make it possible to create the desired flavor profiles.

The Influence of Biomolecule Composition on Colloidal Beer Structure

Recent studies have revealed an interest in the composition of beer biomolecules as a colloidal system and their influence on the formation of beer taste. The purpose of this research was to establish biochemical interactions between the biomolecules of plant-based raw materials of beer in order to understand the overall structure of beer as a complex system of bound biomolecules. Generally accepted methods of analytical research in the field of brewing, biochemistry and proteomics were used to solve the research objectives. The studies allowed us to establish the relationship between the grain and plant-based raw materials used, as well as the processing technologies and biomolecular profiles of beer. The qualitative profile of the distribution of protein compounds as a framework for the formation of a colloidal system and the role of carbohydrate dextrins and phenol compounds are given. This article provides information about the presence of biogenic compounds in the structure of beer that positively affect the functioning of the body. A critical assessment of the influence of some parameters on the completeness of beer taste by biomolecules is given. Conclusion: the conducted analytical studies allowed us to confirm the hypothesis about the nitrogen structure of beer and the relationship of other biomolecules with protein substances, and to identify the main factors affecting the distribution of biomolecules by fractions.