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Characterisation of elderberry fruits
Christovová, Silvia ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This master's thesis deals with the characterization of elderberry fruit (Sambucus nigra L.) with emphasis on the aroma active compounds (AAC) and vitamin C (ascorbic acid (AA), dehydroascorbic acid (DHA)). The theoretical part gives a brief outlook on the chemical composition and attributes of Sambucus berries, its healing properties and the means of processing. The rest of the theoretical part thoroughly examines the AAC and vitamin C. The suitable assessment methods are also discussed. The experimental part of the work consists of two main tasks. The first one was to assess the aroma profile of Sambucus berries using the HS-SPME-GC-FID. 18 samples were examined (the wild elderberry and 17 cultivated varieties). In total, 24 different volatile aroma active compounds were identified and quantified, 12 of which belonged to alcohols, 5 to aldehydes, 4 to esters, 1 to acids and 2 “other” compounds (linalool and -damascenone). The chemical composition of the individual samples was not uniform; no single sample contained all of the identified compounds. The second task was to assess the total vitamin C content (the sum of DHA and AA) using the HPLC. For the purpose of reducing DHA to AA three reducing agents were examined (DTT, TCEP and L-cysteine) at two different pH levels (7 and 4). TCEP at pH 4 turned out to be most efficient and was subsequently applied on the samples of 5 selected elderberry varieties. The measured vitamin C content was within the range of 5,1 – 13,0 mg per 100 g of fruit.
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Monitoring of chemical changes in ground coffee stored in different ways
Lajtman, Roman ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the monitoring of chemical changes in ground coffee stored in various containers and then it deals with the determination of water, moisture and aromatic profile of coffee in individual containers, namely a can, a paper bag, a bag with a polyethylene liner, a bag from low density polyethylene with aluminium liner (LDPE + Al) and a glass container. At the beginning of the experiment it was found that the water content in the coffee was 4.72 ± 0.10 % and the moisture content was 9.47 ± 0.01 %. After the original sample was measured, the coffee was poured into 5 packages. At the end of the experiment, a can was chosen as the most suitable package where the lowest water content was measured. The water content was determined to be 6.51 ± 0.11 % and the moisture content was 9.93 ± 0.01 %. However, the differences between the other packages, apart from the paper bag, were very small, and thus in general it can be said that the can, the LDPE + Al package, the bag with the PE liner and the glass container are suitable for storing ground coffee. A total of 44 aromatics were identified when determining the aromatic profile in coffee by HS-SPME-GC-MS. The most represented groups of substances were furans and pyrazines. During storage, there was some loss of substances due to 2 mechanisms. The first of them is evaporation and the second one is the oxidation reactions themselves. Most aromatic substances have evaporated / degraded in paper packaging, where this large decrease is related to its barrier properties. A glass container was chosen as the most suitable packaging with the least loss of aromatic substances.
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Bioflavouring of beer using new Czech hop varieties
Ondruch, Petr ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on bioflavouring of beer using new czech hop varieties. Dry hopping is a phenomem, that contributes to the attractiveness and diversity of beer and is nowadays gaining in popularity. The aim of this work was to determine the effect of dry hopping on sensory profile and analytical parametrs of dry-hopped beers using czech hop varieties. Sensory evaluation and chemical analysis of these beers were taken. The chemical analysis included determination of the basic beer characteristics, total phenolic a flavonoid content, antioxidant activity and the concentration of selected organic acids and chemical elements. It was found out that dry-hopped beers compared to the reference beer presented higher bitterness, antioxidant activity and contained higher amount of flavonoids. Also an increase in pottasium, manganese, copper, calcium and malic acid levels was reported. The pH of beer samples was not affected by dry hopping. Sensory evaluation showed that dry hopping had a positive influence on the overall enjoyment of the beer, which was mainly determined by the higher aroma and more intense bitterness. By summaring all the data, it is obvious that dry hopping of beer using new czech hop varieties has a positive effect on the quality of the final beer and these hop varities are suitable for further use in the beer industry.
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Influence of producing technology on flavour of Edam cheese
Urbanová, Andrea ; Buňka, František (referee) ; Vítová, Eva (advisor)
This work deals with the problem of flavour of Edam cheeses, i.e. natural hard cheese with low heat curd. The samples came from dairy MILTRA B s. r. o. Městečko Trnávka. A number of aroma active substances contribute to flavour of cheese. From the chemical point of view they are volatile compounds, including alcohols, aldehydes, ketones, fatty acids, esters, lactones, terpenes etc. Their content increases during ripening by influence of proteolytic and lipolytic changes and creates aroma, which is characteristic for type of cheese. The development of these components was monitored in chosen Edam cheese (30 % fat in dry matter) by headspace-SPME/GC method. The fiber CARTM/PDMS 85 µm was used for extraction of aroma compounds. The samples were taken from cheesemilk up to technologically ripe cheese. In total 30 aromatic compounds were identified, their content increased during ripening. The first increase was observed after pressing and then especially in second part of ripening. For comparison Edam cheese samples were also sensorially evaluated during ripening. The ordinal scale and profile tests were used for evaluation of organoleptic properties (appearance, texture, taste, aroma). The sensory quality was improved during ripening, but significant changes were not observed with regard to fine taste and smell of Edam cheese given by globally low content of aroma active compounds.
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The portable device for aroma detecting in food industry
Beneš, David ; Jankovský, Jaroslav (referee) ; Adámek, Martin (advisor)
This work deals with the construction of a simple cheap portable device that allows the measurement and recognition of aromas in food industry using semiconductor gas sensors with the ability to share measurement data to a remote server. The device is controlled by Arduino development platform, enriched by two modules. Work shortly apprises readers with aroma monitoring in food industry and development board Arduino which contains ATMega series microcontroller and with module for network communication. This work also includes a measurement sample and review using the proposed circuit.
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Bioflavouring of low alcoholic beer by dry hopping
Dušánek, Václav ; Mikulíková, Renata (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the influence of cold hopping of low-alcohol beers on analytical properties and sensory profile of beer. The effect of cold hopping was observed using the varieties Kazbek, Jazz, Mimosa and Uran. In the experimental part, the production process of low-alcohol beer using immobilized yeast is described. After the main fermentation, the low-alcohol beer was kegged into five cuvettes and after 20 days cold-hopped at a dose of 3 g/l with individual varieties. The effect of cold hopping with individual varieties on the organoleptic properties of the beer was observed. Bitterness was determined, with cold-hopped beers showing an increase between 17-24 % in bitterness. Furthermore, the ethanol content was determined by high-performance liquid chromatography at 2,14 % vol. A significant increase in all volatiles, in particular -myrcene and linalool, was found in the cold-hopped beers by gas chromatography with mass spectrometry. The sensory analysis showed that the cold hopping had a positive effect on the overall impression and masked the taste defects of the reference low-alcohol beer. The best hop evaluated for the use of the cold hopping method was the Kazbek variety. The Jazz and Mimosa varieties were also perceived relatively positively by the evaluators. On the other hand, the Uran variety achieved a worse overall impression than the reference beer.
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Possibilities of using spices in the production of ham salami
Vershinina, Alina ; Szotkowski, Martin (referee) ; Mikulíková, Renata (advisor)
This bachelor's thesis focuses on the possibilities of using different spices, specifically cumin, nutmeg, allspice and marjoram, in the production of ham cuts. The aim of the work is to investigate the effect of these spices on the taste, aroma and other sensory properties of the ham cut and to assess their contribution to improving the overall quality of the product. The methodology includes the collection of samples of ham cut with various additions of spices, the performance of sensory analysis and chemical analysis for the identification and quantification of phenolic substances present in individual spices. Subsequently, the results will be evaluated and their significance for the production of ham cuts will be discussed. The results of this work could contribute to a better understanding of the use of spices in the production of meat products and provide data for the optimization of recipes and processes in the food industry.
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Bioflavouring of beer using new Czech hop varieties
Ondruch, Petr ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on bioflavouring of beer using new czech hop varieties. Dry hopping is a phenomem, that contributes to the attractiveness and diversity of beer and is nowadays gaining in popularity. The aim of this work was to determine the effect of dry hopping on sensory profile and analytical parametrs of dry-hopped beers using czech hop varieties. Sensory evaluation and chemical analysis of these beers were taken. The chemical analysis included determination of the basic beer characteristics, total phenolic a flavonoid content, antioxidant activity and the concentration of selected organic acids and chemical elements. It was found out that dry-hopped beers compared to the reference beer presented higher bitterness, antioxidant activity and contained higher amount of flavonoids. Also an increase in pottasium, manganese, copper, calcium and malic acid levels was reported. The pH of beer samples was not affected by dry hopping. Sensory evaluation showed that dry hopping had a positive influence on the overall enjoyment of the beer, which was mainly determined by the higher aroma and more intense bitterness. By summaring all the data, it is obvious that dry hopping of beer using new czech hop varieties has a positive effect on the quality of the final beer and these hop varities are suitable for further use in the beer industry.
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Monitoring of chemical changes in ground coffee stored in different ways
Lajtman, Roman ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the monitoring of chemical changes in ground coffee stored in various containers and then it deals with the determination of water, moisture and aromatic profile of coffee in individual containers, namely a can, a paper bag, a bag with a polyethylene liner, a bag from low density polyethylene with aluminium liner (LDPE + Al) and a glass container. At the beginning of the experiment it was found that the water content in the coffee was 4.72 ± 0.10 % and the moisture content was 9.47 ± 0.01 %. After the original sample was measured, the coffee was poured into 5 packages. At the end of the experiment, a can was chosen as the most suitable package where the lowest water content was measured. The water content was determined to be 6.51 ± 0.11 % and the moisture content was 9.93 ± 0.01 %. However, the differences between the other packages, apart from the paper bag, were very small, and thus in general it can be said that the can, the LDPE + Al package, the bag with the PE liner and the glass container are suitable for storing ground coffee. A total of 44 aromatics were identified when determining the aromatic profile in coffee by HS-SPME-GC-MS. The most represented groups of substances were furans and pyrazines. During storage, there was some loss of substances due to 2 mechanisms. The first of them is evaporation and the second one is the oxidation reactions themselves. Most aromatic substances have evaporated / degraded in paper packaging, where this large decrease is related to its barrier properties. A glass container was chosen as the most suitable packaging with the least loss of aromatic substances.
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Možnosti využití kořenících směsí a aromat v pekárenství a těstárenské výrobě
Skácelová, Andrea
My master thesis: The Possibilities of spice blends and flavors in baked goods and pasta production deals with the use of spice mixtures in an unusual way. In this thesis, spices are described in great thought and detail, then focuses on the description of baked goods and pasta production. The practical part of this paper is created and tested from recipes for bread production using various mixtures of spices and tested by sensory and instrumental analysis. Additionally, the pastas were prepared with mixtures of spices, sensory assessment, and laboratory analysis. The results were summarized in tables and graphs, and evaluated by available statistical methods.
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