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The influence of type of dry hopping on the senzomic and sensory profile of top fermented beer
Bečková, Alena ; prof.Ing.Pavel Dostálek, CSc. (referee) ; Olšovská,, Jana (advisor)
The thesis is focused on the effect of dry hopping on beer senzomy and sensory profile of the top-fermented beer. The goal of this work was to modify samples of the top-fermented beer by dry hopping, to analyze them by senzomy and sensory way, to optimize the method for hop essential oils analysis and to compare the results to the available literature. The problematics of the used raw materials, analyzed substances, technological and analytical methods are discussed in the theoretical part. The practical part is composed of technological preparation of the samples and their analysis. There was used a commercial product of the type of American Indian Pale Ale in this work. There was added a Cascade hop by dry hopping into the commercial product. The basic analysis of gravity and attenuation of the beer were done on the fresh beer and the two months old beer. The selected essential oils, carbonyl compounds, bitter acids, selected metal contaminant and nitrates were established in the beer and in the hop. The samples of the beer were sensory evaluated in the same two-month interval. It was determined that the dry hopping influenced the increased pH of the beer. There was established the quantity of essentials oils in the samples and it was compared to the sensorial results. These results can be used as a base for the next exploration, some part of the results are applicable in the beer industry.
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Characterization of new czech hop varieties
Faruzel, Vojtěch ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
In this thesis the problem of characterization of new Czech hop varieties was investigated. The selected new varieties were Mimosa, Jazz and Blues. Their composition was compared with the widely used varieties Žatecký poloraný červeňák and Kazbek. The content of -bitter acids and -bitter acids, total phenolic content, flavonoid content and antioxidant activity were determined by UV-VIS spectroscopy for all hop varieties. The composition of hop essential oils was estimated by SPME-GC-MS. The diversity of the hop varieties was confirmed from the measured data by statistical analysis. The new varieties showed statistically significant differences in all monitored parameters, especially in comparison with the varieties Žatecký poloraný červeňák and Kazbek. The quantitatively different representation of -bitter acids and -bitter acids has an influence on the character and intensity of bitterness of these hop varieties. The composition of the hop essential oils, the content of phenolic substances, flavonoids and antioxidant activity are reflected in the different organoleptic properties of the hops analysed and of the beer.
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Determination of essential oils in hops and beer by GC-MS method
Přikryl, Jaroslav ; Sobotníková, Jana (advisor) ; Nesvadba, Vladimír (referee)
The submitted master's thesis aims to the analysis of hop essential oils using gas chromatography separation and subsequent determination using a pair of mass and flame ionization detectors. In the first part, the thesis focuses on the theoretical approach to the issue of hop essential oils and the technical functionality of the device for the detection and quantitative determination of essential oils. Subsequently, in the second part, work describes the development, optimization and validation of the newly developed method for the extraction and determination of hop essential oil.
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Characterization of new czech hop varieties
Faruzel, Vojtěch ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
In this thesis the problem of characterization of new Czech hop varieties was investigated. The selected new varieties were Mimosa, Jazz and Blues. Their composition was compared with the widely used varieties Žatecký poloraný červeňák and Kazbek. The content of -bitter acids and -bitter acids, total phenolic content, flavonoid content and antioxidant activity were determined by UV-VIS spectroscopy for all hop varieties. The composition of hop essential oils was estimated by SPME-GC-MS. The diversity of the hop varieties was confirmed from the measured data by statistical analysis. The new varieties showed statistically significant differences in all monitored parameters, especially in comparison with the varieties Žatecký poloraný červeňák and Kazbek. The quantitatively different representation of -bitter acids and -bitter acids has an influence on the character and intensity of bitterness of these hop varieties. The composition of the hop essential oils, the content of phenolic substances, flavonoids and antioxidant activity are reflected in the different organoleptic properties of the hops analysed and of the beer.
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Study of sensory-active compounds of hops in dry-hopped beers
Zlochová, Tereza ; Sobotníková, Jana (advisor) ; Jelínek, Ivan (referee)
Study of sensory-active compounds of hops in dry-hopped beers Key words: hop, hop oils, dry-hopping, beer, beer-aging, beer sensory analysis Nowadays, dry-hopping is a widely used method of beer making, with its pros and cons. The main purpose of dry-hopping is to derive specific hop aroma to beer in its very unchanged form. The essential part of this work consists of a study of hop essential oils, as the main providers of desired hop aroma. Firstly, the validation of methods for isolating essential oils from hop material and beer is carried out. Secondly, the transfer of these volatiles in process of dry-hopping is studied and the impact on beer aroma profile is discussed. Subsequently, changes of essential oils profile during beer-aging are observed and evaluated with a valuable tool, the sensory analysis. This study was realized on beer samples from Brewers' Choice program, thanks to the Research Institute of Brewing and Malting and Lenka Strakova, the Pilsner Urquell brewer.
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The influence of type of dry hopping on the senzomic and sensory profile of top fermented beer
Bečková, Alena ; prof.Ing.Pavel Dostálek, CSc. (referee) ; Olšovská,, Jana (advisor)
The thesis is focused on the effect of dry hopping on beer senzomy and sensory profile of the top-fermented beer. The goal of this work was to modify samples of the top-fermented beer by dry hopping, to analyze them by senzomy and sensory way, to optimize the method for hop essential oils analysis and to compare the results to the available literature. The problematics of the used raw materials, analyzed substances, technological and analytical methods are discussed in the theoretical part. The practical part is composed of technological preparation of the samples and their analysis. There was used a commercial product of the type of American Indian Pale Ale in this work. There was added a Cascade hop by dry hopping into the commercial product. The basic analysis of gravity and attenuation of the beer were done on the fresh beer and the two months old beer. The selected essential oils, carbonyl compounds, bitter acids, selected metal contaminant and nitrates were established in the beer and in the hop. The samples of the beer were sensory evaluated in the same two-month interval. It was determined that the dry hopping influenced the increased pH of the beer. There was established the quantity of essentials oils in the samples and it was compared to the sensorial results. These results can be used as a base for the next exploration, some part of the results are applicable in the beer industry.
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Determination of sensory active compounds in hops using GC-MS
Zlochová, Tereza ; Sobotníková, Jana (advisor) ; Čejka, Pavel (referee)
Determination of sensory active compounds in hops using GC-MS Abstract The goal of this thesis was to determine sensory active compounds from a sample of hops by gas chromatographic-mass spectrometric detection. Hop oils were selected for this determination which, despite its low representation in hops, contain up to several hundred components. Hop oils were exctracted using a new method based on fluidized-bed extraction. An integral part of this work was identifying the yield of the method that has become an instrument to defining the content of hop oils in different hop varieties. A comparsion of the obtained extracts with the literature was made and a search was done for the link between chemical structure of the hop oils and their representation in the hops sample with regard to its age. Keywords: exctraction, hops, hop oil, gas chromatography, mass spectrometry
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Variabilita obsahu silic ve chmelových šišticích
Křížová, Alena
This thesis deals with the variability of hop oils in the hop cones. Hops is the most important raw material for the production of beer and hop oils are the most important group of compounds responsible for the aroma of hops and thus the beer. Essential oils are applied in commercial quality assessment of cone hops for beer production. Essential oils have also hop buffer and antibacterial effects and pharmacology are used for suppressing agitation, restlessness and insomnia. Essential oils are complex mixtures of hundreds of natural compounds of different chemical composition. They represent a mixture of carbon compounds, oxygen compounds and sulfur compounds. The content of hop oils in the hop cones depends on the genetic characteristics of the variety, growing area, the average temperature, rainfall, and other conditions cultivation. This work was performed by steam distillation determination of hop oils. The determination was carried out on samples from 2012 and 2013, the essential oil content was profitable in 2012. Highest value of the hop oils was measured in a variety of Premiant from Tršice growing region (837 micro liters.100g-1). The lowest value then the variety Saaz classical form of the Saaz hop-growing area (220 mocro liters.100g-1).
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