Brewing recipe design is mainly based on brewer’s expertise, information available in catalogs and certificates of analysis (CoA’s). Hop schedule design and formulation has become an essential topic since hoppy craft beers took the scene. But how accurate is the flavor profile information provided in catalogs? How useful is the chemical composition profile information in CoA’s? Besides current research and tons of reported experiences, hops impact is still a mystery, and topics like biotransformation are black-boxes for brewers. In this study, nine single hopped beers were brewed, and a trained panel conducted sensorial beer analysis. Then, to asses hop impact, qualitative and process-related-quantitative beer characteristics were contrasted to find valuable correlations and trends between hop catalogs and final beers. Discrepancies with catalog qualitative data were reported. In addition to what is already described in the literature, here we describe how α-acids, linalool, myrcene, and geraniol (despite the classical use for these compounds) could predict positive and negative hop impact of nine different hop varieties on bitterness, flavor, and aroma, when they are applied in different brewing process steps. Also, with this pipeline we stand the basis of a tool to be improved, available for brewers, to better predict their brews and assess new hop varieties in real-life pilot brewing set ups.
{"title":"Finding correlations between hop catalogs and real hoppy character in brewery conditions","authors":"Danilo Legisa, Hernan Mengoni","doi":"10.18832/kp2021.67.537","DOIUrl":"https://doi.org/10.18832/kp2021.67.537","url":null,"abstract":"Brewing recipe design is mainly based on brewer’s expertise, information available in catalogs and certificates of analysis (CoA’s). Hop schedule design and formulation has become an essential topic since hoppy craft beers took the scene. But how accurate is the flavor profile information provided in catalogs? How useful is the chemical composition profile information in CoA’s? Besides current research and tons of reported experiences, hops impact is still a mystery, and topics like biotransformation are black-boxes for brewers. In this study, nine single hopped beers were brewed, and a trained panel conducted sensorial beer analysis. Then, to asses hop impact, qualitative and process-related-quantitative beer characteristics were contrasted to find valuable correlations and trends between hop catalogs and final beers. Discrepancies with catalog qualitative data were reported. In addition to what is already described in the literature, here we describe how α-acids, linalool, myrcene, and geraniol (despite the classical use for these compounds) could predict positive and negative hop impact of nine different hop varieties on bitterness, flavor, and aroma, when they are applied in different brewing process steps. Also, with this pipeline we stand the basis of a tool to be improved, available for brewers, to better predict their brews and assess new hop varieties in real-life pilot brewing set ups.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88207008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A miniaturized and improved method for Apparent Total Nitroso Compounds determination in liquid matrices was developed. The main improvement is based on a miniaturized and modified apparatus for chemical denitrosation of nitroso compounds by hydrogen bromide in a glacial acetic acid mixture. The reaction is carried out in a teflon reaction coil while the reaction product, gaseous nitric oxide, is drifted to a chemiluminescence detector by the flow of argon together with a vacuum obtained by the detector's oil pump. The apparatus significantly increased the efficiency of the Apparent Total N-Nitroso Compounds determination (compared to the previous method), specifically, the dead volume of the apparatus was significantly decreased, and the effect of the reverse reaction was eliminated as well. The apparatus shortens the analysis time (1.4 min/injection), further it provides a lower detection limit (3 μg(N-NO)/l), quantification limit (10 μg(N-NO)/l), and method uncertainty (15%), and is simpler for the operation.
{"title":"Miniaturized and improved method for Apparent Total N-Nitroso Compounds determination in beer","authors":"Tomáš Vrzal, M. Malečková, J. Olšovská","doi":"10.18832/kp2021.67.498","DOIUrl":"https://doi.org/10.18832/kp2021.67.498","url":null,"abstract":"A miniaturized and improved method for Apparent Total Nitroso Compounds determination in liquid matrices was developed. The main improvement is based on a miniaturized and modified apparatus for chemical denitrosation of nitroso compounds by hydrogen bromide in a glacial acetic acid mixture. The reaction is carried out in a teflon reaction coil while the reaction product, gaseous nitric oxide, is drifted to a chemiluminescence detector by the flow of argon together with a vacuum obtained by the detector's oil pump. The apparatus significantly increased the efficiency of the Apparent Total N-Nitroso Compounds determination (compared to the previous method), specifically, the dead volume of the apparatus was significantly decreased, and the effect of the reverse reaction was eliminated as well. The apparatus shortens the analysis time (1.4 min/injection), further it provides a lower detection limit (3 μg(N-NO)/l), quantification limit (10 μg(N-NO)/l), and method uncertainty (15%), and is simpler for the operation.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"32 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91456451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Kubizniaková, L. Kyselová, M. Brožová, Katarína Hanzalíková, D. Matoulková
Acetic acid bacteria (AAB) are often considered a threat of the past because today’s equipment allows to perform post-fermentation processes under greatly reduced level of oxygen. This paper deals with the current importance of AAB in brewing. The risk of contamination as well as functional role in spontaneously fermented sour beers is reviewed. The main harmful effect of AAB lies in the direct spoilage of draft beer and formation of biofilms, most often in dispensing systems. On contrary AAB seems to be indispensable in the case of sour beer production. A key issue of AAB in brewing environment is their (early) detection and identification. Therefore, part of this study is devoted to both the latest sophisticated methods and also those of traditional cultivation. which are still prevalent in operating laboratories due to their cost and easy implementation. Finally, the experimental and pictorial material is added as a guide for operations that have less experience with AAB.
{"title":"The role of acetic acid bacteria in brewing and their detection in operation","authors":"P. Kubizniaková, L. Kyselová, M. Brožová, Katarína Hanzalíková, D. Matoulková","doi":"10.18832/kp2021.67.511","DOIUrl":"https://doi.org/10.18832/kp2021.67.511","url":null,"abstract":"Acetic acid bacteria (AAB) are often considered a threat of the past because today’s equipment allows to perform post-fermentation processes under greatly reduced level of oxygen. This paper deals with the current importance of AAB in brewing. The risk of contamination as well as functional role in spontaneously fermented sour beers is reviewed. The main harmful effect of AAB lies in the direct spoilage of draft beer and formation of biofilms, most often in dispensing systems. On contrary AAB seems to be indispensable in the case of sour beer production. A key issue of AAB in brewing environment is their (early) detection and identification. Therefore, part of this study is devoted to both the latest sophisticated methods and also those of traditional cultivation. which are still prevalent in operating laboratories due to their cost and easy implementation. Finally, the experimental and pictorial material is added as a guide for operations that have less experience with AAB.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75741626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Honey mead is a well-known conventional alcoholic beverage made by microbial fermentation of diluted honey. The selection of prospective yeasts for inoculation of honey-must with regard to honey mead quality determines the quality of mead production. The yeast consortium tolerant to ethanol stress was selected for this study using an enrichment technique. The activity of the invertase enzyme and the level of ethanol tolerance have been investigated. Thai stingless bee honey was used as a substrate, and the selected ethanol tolerant yeast consortium was used for mead fermentation. The results revealed that the PP03 had the highest invertase activity of 75.13±9.16 U/mL and the highest ethanol tolerance level of 12%. This is the first study using an ethanol tolerant yeast consortium to ferment honey mead from Thai stingless bee honey.
{"title":"Honey Mead Fermentation from Thai Stingless Bee (Tetragonula leaviceps) Honey using Ethanol Tolerant Yeast","authors":"Pimprapa Chaijak, Purimprach Sinkan, Santipap Sotha","doi":"10.18832/kp2021.67.503","DOIUrl":"https://doi.org/10.18832/kp2021.67.503","url":null,"abstract":"Honey mead is a well-known conventional alcoholic beverage made by microbial fermentation of diluted honey. The selection of prospective yeasts for inoculation of honey-must with regard to honey mead quality determines the quality of mead production. The yeast consortium tolerant to ethanol stress was selected for this study using an enrichment technique. The activity of the invertase enzyme and the level of ethanol tolerance have been investigated. Thai stingless bee honey was used as a substrate, and the selected ethanol tolerant yeast consortium was used for mead fermentation. The results revealed that the PP03 had the highest invertase activity of 75.13±9.16 U/mL and the highest ethanol tolerance level of 12%. This is the first study using an ethanol tolerant yeast consortium to ferment honey mead from Thai stingless bee honey.\u0000 ","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85466712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Piacentini, S. Běláková, L. Rocha, G. Savi, K. Benešová, M. Pernica, I. Hartman, J. Čáslavský, R. Boško, B. Côrrea
Hydrophobins produced by the Fusarium genus in brewing barley in connection with gushing phenomenon have been studied in many different countries. However, the presence of proteins associated with gushing in grains harvested in Brazil is currently unknown. The surface active class 2 hydrophobin Hyd5 has been identified as a possible causative agent for gushing of beer. For this reason, the objective of this study was to evaluate the presence of Hyd5 in isolated Fusarium strains from Brazilian barley samples. This was followed by gushing tests. The Hyd5 gene was identified in all fungal isolates and phylogenetic analysis exhibited four main linages. Gushing tests demonstrated that among the 21 analysed malt samples 8 were positive considering overfoaming at the bottle opening. Levels ranged from 8 to 124 g/bottle of gushing. No correlation between phylogenetic analysis and gushing was observed when they were evaluated together. This is due to positive isolates for gushing which are scattered throughout the phylogenetic tree. The other cause may be that all main clades contain at least one positive isolate for gushing. More research regarding hydrophobins and gushing should be carried out in the future due to the fungi isolated in Brazilian samples. These results offer excellent support that could help the brewing industry to prevent its losses and to provide further understanding of the gushing phenomenon in beer.
{"title":"Gushing phenomenon and gene Hyd5 from Fusarium species in barley samples from Brazil","authors":"K. Piacentini, S. Běláková, L. Rocha, G. Savi, K. Benešová, M. Pernica, I. Hartman, J. Čáslavský, R. Boško, B. Côrrea","doi":"10.18832/KP2021.67.435","DOIUrl":"https://doi.org/10.18832/KP2021.67.435","url":null,"abstract":"Hydrophobins produced by the Fusarium genus in brewing barley in connection with gushing phenomenon have been studied in many different countries. However, the presence of proteins associated with gushing in grains harvested in Brazil is currently unknown. The surface active class 2 hydrophobin Hyd5 has been identified as a possible causative agent for gushing of beer. For this reason, the objective of this study was to evaluate the presence of Hyd5 in isolated Fusarium strains from Brazilian barley samples. This was followed by gushing tests. The Hyd5 gene was identified in all fungal isolates and phylogenetic analysis exhibited four main linages. Gushing tests demonstrated that among the 21 analysed malt samples 8 were positive considering overfoaming at the bottle opening. Levels ranged from 8 to 124 g/bottle of gushing. No correlation between phylogenetic analysis and gushing was observed when they were evaluated together. This is due to positive isolates for gushing which are scattered throughout the phylogenetic tree. The other cause may be that all main clades contain at least one positive isolate for gushing. More research regarding hydrophobins and gushing should be carried out in the future due to the fungi isolated in Brazilian samples. These results offer excellent support that could help the brewing industry to prevent its losses and to provide further understanding of the gushing phenomenon in beer.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"64 1","pages":"435-441"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84226075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new simultaneous method for determination of 16 heterocyclic compounds using SPE sample preparation and GC-MS determination was developed regarding increasing interest of the role of sensory active compounds in beer. LiChrolut® EN SPE columns proved to be optimal for both, a mixture of analytes with a different polarity and such complicated matrix as beer. Recoveries of individual analytes are about 100% except for three compounds (2-methylpyridine about 30%, maltol and furaneol about 50%); repeatability, uncertainty and LOQ are satisfactory for the method application. The method was used for monitoring of heterocyclic compounds formation during roasting, mashing, hop boiling and fermentation. To summarize, during roasting of malt, the concentration of oxygen heterocycle compounds (OHC) increases more rapidly in comparison with nitrogen heterocycles compounds (NHC) till a critical point where OHC starts to decrease and NHC starts to be formed sharper (with the exception of 2-acetylpyrrole which is similar to OHC). Finally, the total concentration of NHC during fermentation rapidly decreases whilst the OHC concentration is influenced by many factors, e.g., fermentation conditions and yeast strain.
{"title":"Novel method for determination of heterocyclic compounds and their impact in brewing technology","authors":"J. Olšovská, K. Štěrba, Martin Slabý, Tomáš Vrzal","doi":"10.18832/KP2021.67.417","DOIUrl":"https://doi.org/10.18832/KP2021.67.417","url":null,"abstract":"A new simultaneous method for determination of 16 heterocyclic compounds using SPE sample preparation and GC-MS determination was developed regarding increasing interest of the role of sensory active compounds in beer. LiChrolut® EN SPE columns proved to be optimal for both, a mixture of analytes with a different polarity and such complicated matrix as beer. Recoveries of individual analytes are about 100% except for three compounds (2-methylpyridine about 30%, maltol and furaneol about 50%); repeatability, uncertainty and LOQ are satisfactory for the method application. The method was used for monitoring of heterocyclic compounds formation during roasting, mashing, hop boiling and fermentation. To summarize, during roasting of malt, the concentration of oxygen heterocycle compounds (OHC) increases more rapidly in comparison with nitrogen heterocycles compounds (NHC) till a critical point where OHC starts to decrease and NHC starts to be formed sharper (with the exception of 2-acetylpyrrole which is similar to OHC). Finally, the total concentration of NHC during fermentation rapidly decreases whilst the OHC concentration is influenced by many factors, e.g., fermentation conditions and yeast strain.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"140 1","pages":"417-427"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79976062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Nesvadba, J. Olšovská, L. Strakova, J. Charvátová
Czech hop varieties are evaluated as part of maintenance breeding. Every year, this evaluation includes ten mother plants of each hop variety. Yield is determined in kilograms of fresh hops per plant. The t-test is used to determine significance. Results from the years 2014–2019 show that Gaia and Kazbek have the highest yield (3.17 kg/plant and 3.05 kg/plant, respectively). Their yield is higher than that of the Harmonie, Agnus, Bohemie, Premiant, Sládek, Boomerang and Saaz varieties. Saaz has the lowest hop yield, i.e. 1.85 kg/plant. Bor, Saaz Late, Saaz and Sládek show the lowest variability, which ranges between 20.56 and 20.58%. Gaia has the highest variability (34.33%). Gaia also has the highest alpha acid content (12.30%) with a probability of 95% to 99%. Vital and Boomerang have a higher alpha acid content than other Czech hop varieties (11.09% and 10.81%, respectively) with a probability of 99%. Saaz Late (3.42%) and Saaz (3.06%) have the lowest alpha acid content with a probability of 95% to 99%. The variability of alpha acid content is considerably lower than the hop yield variability. Rubín has the lowest year-on-year variability of all Czech varieties (4.81%). Vital and Gaia have a very low variability (5.63% and 5.72%, respectively). A higher variability of alpha acid content was found in Saaz Late, Premiant, Agnus, Saaz, Kazbek, Bor and Harmonie, ranging between 8.01% and 10.21%.
{"title":"Evaluation of Czech hop varieties","authors":"V. Nesvadba, J. Olšovská, L. Strakova, J. Charvátová","doi":"10.18832/KP2021.67.428","DOIUrl":"https://doi.org/10.18832/KP2021.67.428","url":null,"abstract":"Czech hop varieties are evaluated as part of maintenance breeding. Every year, this evaluation includes ten mother plants of each hop variety. Yield is determined in kilograms of fresh hops per plant. The t-test is used to determine significance. Results from the years 2014–2019 show that Gaia and Kazbek have the highest yield (3.17 kg/plant and 3.05 kg/plant, respectively). Their yield is higher than that of the Harmonie, Agnus, Bohemie, Premiant, Sládek, Boomerang and Saaz varieties. Saaz has the lowest hop yield, i.e. 1.85 kg/plant. Bor, Saaz Late, Saaz and Sládek show the lowest variability, which ranges between 20.56 and 20.58%. Gaia has the highest variability (34.33%). Gaia also has the highest alpha acid content (12.30%) with a probability of 95% to 99%. Vital and Boomerang have a higher alpha acid content than other Czech hop varieties (11.09% and 10.81%, respectively) with a probability of 99%. Saaz Late (3.42%) and Saaz (3.06%) have the lowest alpha acid content with a probability of 95% to 99%. The variability of alpha acid content is considerably lower than the hop yield variability. Rubín has the lowest year-on-year variability of all Czech varieties (4.81%). Vital and Gaia have a very low variability (5.63% and 5.72%, respectively). A higher variability of alpha acid content was found in Saaz Late, Premiant, Agnus, Saaz, Kazbek, Bor and Harmonie, ranging between 8.01% and 10.21%.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"7 1","pages":"428-434"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87366463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marta Zavřelová, V. Psota, P. Matušinský, M. Musilová, Michaela Némethová
A set of 92 genetic resources of spring barley split into groups according to the areas of origin was studied in terms of grain malting quality. The following malting parameters were monitored in this study: nitrogen content in barley grain, malt extract, relative extract at 45 °C, Kolbach index, diastatic power, apparent final attenuation, friability, β-glucans in wort, haze of wort measured at the angles of 15° and 90°. In the studied set, the largest variability was found in the haze of wort (90°), the smallest in the apparent final attenuation. The optimal values of the extract content in the malt dry matter according to the malting quality index were only detected in the genotypes originating from Europe (groups A and B). The group of the genetic resources from South America and Australia, together with the genotypes from the Middle East and Africa, differed statistically significantly in the values of the Kolbach index from other groups. The two-row genotypes differed statistically significantly in the values of malt extract content, relative extract at 45 °C, Kolbach index, diastatic power, friability and β-glucan content in wort. Although the European and non-European groups differed in a number of traits, the non-European groups also included genetic resources that in their malting parameters approached or equalled the European malting varieties (such as Psaknon). In this study, several significant correlations were found; the strongest correlations were between friability and malt extract (r = 0.85), friability and Kolbach index (r = 0.84).
{"title":"Evaluation of malting quality of spring barley genetic resources from different regions of origin","authors":"Marta Zavřelová, V. Psota, P. Matušinský, M. Musilová, Michaela Némethová","doi":"10.18832/KP2021.67.392","DOIUrl":"https://doi.org/10.18832/KP2021.67.392","url":null,"abstract":"A set of 92 genetic resources of spring barley split into groups according to the areas of origin was studied in terms of grain malting quality. The following malting parameters were monitored in this study: nitrogen content in barley grain, malt extract, relative extract at 45 °C, Kolbach index, diastatic power, apparent final attenuation, friability, β-glucans in wort, haze of wort measured at the angles of 15° and 90°. In the studied set, the largest variability was found in the haze of wort (90°), the smallest in the apparent final attenuation. The optimal values of the extract content in the malt dry matter according to the malting quality index were only detected in the genotypes originating from Europe (groups A and B). The group of the genetic resources from South America and Australia, together with the genotypes from the Middle East and Africa, differed statistically significantly in the values of the Kolbach index from other groups. The two-row genotypes differed statistically significantly in the values of malt extract content, relative extract at 45 °C, Kolbach index, diastatic power, friability and β-glucan content in wort. Although the European and non-European groups differed in a number of traits, the non-European groups also included genetic resources that in their malting parameters approached or equalled the European malting varieties (such as Psaknon). In this study, several significant correlations were found; the strongest correlations were between friability and malt extract (r = 0.85), friability and Kolbach index (r = 0.84).","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"50 1","pages":"392-402"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83269775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Mikyška, K. Štěrba, Martin Slabý, M. Jurkovă, A. Kopecký, František Kroupa
The specification of varietal profiles of secondary metabolites of hops in beer is of considerable importance for hop growing and beer brewing. In three-year pilot (200 l) brews of Czech pale lager, the chemical and sensory profiles of beers hopped with the Saaz Special variety or the traditional Saaz semi-early red bine hops (Saaz) variety were compared. Single kettle hopped beers and single kettle + dry hopped beers were prepared. The overall sensory impression of the Saaz Special beers was comparable to Saaz hops, the profile of essential oils and hop aromas/flavors in beer was partially different, but the hop aroma was not rated worse than Saaz. Saaz Special dry hopped beers were clearly distinguished from Saaz in triangle tests, but without the preference of one of the varieties. Based on the achieved results, the Saaz Special variety was included in the list of varieties recommended for the production of beer with the Protected Geographical Indication Czech beer.
{"title":"Saaz Special – another hop variety recommended for Czech beer","authors":"A. Mikyška, K. Štěrba, Martin Slabý, M. Jurkovă, A. Kopecký, František Kroupa","doi":"10.18832/KP2021.67.409","DOIUrl":"https://doi.org/10.18832/KP2021.67.409","url":null,"abstract":"The specification of varietal profiles of secondary metabolites of hops in beer is of considerable importance for hop growing and beer brewing. In three-year pilot (200 l) brews of Czech pale lager, the chemical and sensory profiles of beers hopped with the Saaz Special variety or the traditional Saaz semi-early red bine hops (Saaz) variety were compared. Single kettle hopped beers and single kettle + dry hopped beers were prepared. The overall sensory impression of the Saaz Special beers was comparable to Saaz hops, the profile of essential oils and hop aromas/flavors in beer was partially different, but the hop aroma was not rated worse than Saaz. Saaz Special dry hopped beers were clearly distinguished from Saaz in triangle tests, but without the preference of one of the varieties. Based on the achieved results, the Saaz Special variety was included in the list of varieties recommended for the production of beer with the Protected Geographical Indication Czech beer.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"14 1","pages":"409-416"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87579704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katarína Hanzalíková, P. Kubizniaková, L. Kyselová, D. Matoulková
The aim of the long-term preservation of cells, tissues and organs is to maintain their cellular structures and biological functions for as long as possible. Cryopreservation is a process where biological material is stored and preserved at very low temperatures. However, freezing and thawing processes can cause irreversible cell damage, which is related to formation of ice crystals, osmotic stress, accumulation of reactive forms of oxygen, etc. Therefore the cell viability depends mainly on the freezing rate, the composition of the cryoprotective medium as well as on the thawing rate. Using a suitable cryoprotective medium can increase the viability rate of the yeasts after “revitalization“. Appropriate pre-cultivation before freezing also plays an important role. These facts show that cell freezing and thawing processes must be controlled to avoid cell damage.
{"title":"Cryopreservation: The secret of modern preservation of brewer’s yeasts – minireview","authors":"Katarína Hanzalíková, P. Kubizniaková, L. Kyselová, D. Matoulková","doi":"10.18832/KP2021.67.403","DOIUrl":"https://doi.org/10.18832/KP2021.67.403","url":null,"abstract":"The aim of the long-term preservation of cells, tissues and organs is to maintain their cellular structures and biological functions for as long as possible. Cryopreservation is a process where biological material is stored and preserved at very low temperatures. However, freezing and thawing processes can cause irreversible cell damage, which is related to formation of ice crystals, osmotic stress, accumulation of reactive forms of oxygen, etc. Therefore the cell viability depends mainly on the freezing rate, the composition of the cryoprotective medium as well as on the thawing rate. Using a suitable cryoprotective medium can increase the viability rate of the yeasts after “revitalization“. Appropriate pre-cultivation before freezing also plays an important role. These facts show that cell freezing and thawing processes must be controlled to avoid cell damage.","PeriodicalId":17834,"journal":{"name":"Kvasny prumysl","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77820990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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