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Chemical composition of wine produced from PIWI cultivars
Michálková, Kateřina ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deasl with the chemical charakterization of wine from selected PIWI varieties. The theoretical part describes the general origin and reason for breeding PIWI varieties, a closer characterization of selected three PIWI varieties, Johaniter, Hibernal and Solaris. The next part is devoted to the description of analytical methods that were used to determine the chemical characteristics. The experimental part is developed to the determination of chemical characteristics, namely general characteristics such as alcohol, total phenols, phenolic substances, volatile substances and elemental composition. The results show that are differences between wines from selected PIWI varieties in therms of chemical composition. The most represented organic acid was in the range of 735,1-1286,2mg/l malic acid. This was followed by acetic in the range of 100-400mg/l. The antioxidant activity was determined in the range of 0,2988-0,9683 mmol/l of Trollox and content of total phenols 273,5-390,3mg/l. Of the phenolic substances, gallic acid was the most represented, ranging from 6,9-13,9mg/l. As another, abundant phenolic substances, catechin in the range of 1,6-6,0mg/l was detected. Of the determined elements, phosphorus in the range of 165,4-450,5mg/l was the most represented. Representatives of ethyl ester, ethyl acetate, decanoic acid ethyl acetate and hexanoic acid ethyl ester, were detected as the most abundant volatiles. From the measured data it was evident that wines from PIWI varieties different from standard varieties, especially in the profile of aromatic substances.
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Determination of selected parameters in special types of beers brewed in the Czech Republic
Fähnrichová, Nikola ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with analysis of special types of beer brewed in the Czech Republic using three instrumental methods. Polyphenols were determined by high performance liquid chromatography. To determine organic acids was used ion exchange chromatography. Elementary analysis was performed by inductively coupled plasma optical emission spectrometry. The theoretical part of the work describes technology of beer production, chemical composition of beer, especially groups of substances which were analysed in this thesis. Principle of used methods is also described. The practical part of the work deals with preparation of tested samples, calibration samples and process analysis. The obtained results of analysed substances are summarized in the tables, discussed and compared with results of analysis of other authors. For the analysis it was used eighteen different types of special beer produced in the Czech Republic.
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Influence of coffee making process on chemical composition of brewed coffee
Trenzová, Kristina ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the influence of baristic coffee preparations on the chemical composition of the obtained beverage. Teoretical part of this thesis focuses on coffee growing, processing technology and the chemical composition of coffee beans. In the experimental part were measured samples of espresso coffee, samples prepared by moca pot, flip-drip method, filtrated coffee, samples prepared by french-press technique, vacuum pot samples and boiled coffee. The samples were prepared according to the baristic techniques at first and later with adjusted water and amount of coffee so these methods could be compared with each other. This work focuses on the determination of caffeine and acrylamide content by liquid chromatography, validation of HPLC method, determination of total phenolic content by Folin-Ciocalteu reagent, determination of organic acids by ion chromatography, determination of selected macro and micro elements by inductively coupled plasma in optical emission spectrometry and analysis of aromatic substances using gas chromatography. Based on the processed results and compared methods, it was shown that the moca pot had the greatest influence on the content of caffeine, acrylamide, organic acids and total phenolic substances, and the flip-drip with vacuum pot method had the greatest influence on the content of aromatic substances. From a baristic point of view the highest concentration of caffeine was 3689 mg/l in coffee based on flip-drip method, and concentration of acrylamide was 25,4 mg/l in the coffee based on the same method. The highest value of total phenolic content was determined in moka pot to c = 5,23 g/l. Regarding the mineral representation, the mineral decomposition of coffee beans and espresso were compared, and the highest values were reached by potassium, namely the concentration was 577 mg/l per 1 g of mineralized sample, in the cup of espresso the potassium concentration was 2461 mg/l. The highest content of organic acids was determined in the beverage prepared by moca pot, in terms of selected acids, the largest representation had the succinic acid with the concentration 599,8 mg/l. The highest content of aromatic substances was found in coffee from a moca pot and in coffee by flip-drip method. The biggest part was~made by furfuryl alcohol.
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Chemical and sensory characterization of cider made from apple cultivars ordinarily grown in Czech republic
Strapcová, Zuzana ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
This master thesis deals with the investigation of selected chemical and sensory characteristics of ciders, which were made from four selected apple varieties. The theoretical part describes the chemical composition of apples, cider, the technology of production and production in the world. The next section describes the analytical methods used to determine chemical characteristics not only in ciders but also in other alcoholic beverages. The experimental part focuses on the determination of chemical characteristics such as the content of organic acids, carbohydrates, total phenolic content, alcohol antioxidant activity and elemental composition. The purpose of the work was to find out how different varieties differ in chemical composition. The produced ciders were subjected to sensory analysis to evaluate the selected cider sensory parameters, which were in the natural state and with the addition of carbon dioxide. The results show that ciders of different varieties differ in chemical composition. Malic acid was the most cider's abundant of the organic acids in the range of 2759 – 4411 mg·l-1. Another acid represented was lactic acid in the range of 166,2 – 288,1 mg·l-1. The glucose content of each cider was determined between 845,3 – 1159,8 mg·l-1and fructose 32,6 – 406,7 mg·l-1. Potassium 944,29 – 1073,98 mg·l-1 was the most represented of all elements. The total phenolic content was determined to be in the range of 164,2 – 214,1 mg of GAE·l-1and the antioxidant activity of 0,192 – 0,318 mg·l-1. These differences in chemical composition were also reflected in sensory evaluation. According to the overall assessment, the best cider was made from the Granny Smith variety, which contained the most organic acids and carbohydrates. It has been found that by adding carbon dioxide, sensory parameters such as colour, taste and smell are altered.
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Evaluation of the influence of the pasterization and filtration on selected chemical components of beer
Vopelková, Dominika ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
The aim of this work was to study the influence of the pasteurization and filtration on selected chemical compounds in beer. Specifically, the influence on elemental composition, content of organic acids, carbohydrates and phenolic substances was studied. Optical emission spectrometry with inductively coupled plasma (ICP-OES) was used for elemental analysis of beer. Analysis of organic acids was evaluated by Ion chromatography. For analysis of carbohydrates was used High performance liquid chromatography with ELSD detector (HPLC-ELSD), phenolic compounds was evaluated by HPLC with diode array detector (HPLC-DAD). Data from analysis of beer was performed by usage of statistical methods (analysis of variance and principal component analysis). Parameters that showed the most significant differences between individual groups of beers were obtained. Correlations between the variables and the technological beer processing operations were found. 12 parameters of total 23 were affected. The effect of filtration and pasteurization was observed in content of the iron, silicon, potassium and magnesium, malate, monosaccharides glucose and fructose and phenolic compounds.
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Determination of organic acids in wine
Michálková, Kateřina ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
This bachelor thesis deals with determination of organic acids in wine by capillary zone isotachophoresis method. The theoretical part is devoted to the properties of wine, its composition, its benefit to human health and capillary zone isotachophoresis and its practical use. The practical part deals with determination of organic acids in wine by capillary zone isotachophoresis. Organic acids are determined in three phases of white and red wine production.
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Evaluation of Physical and Chemical Parameters of Still Less Exploited Species of Small Fruit and Proposal of a New Soft Drink from this Fruit
Cetkovská, Jitka ; Krška,, Boris (referee) ; Barták,, Petr (referee) ; Omelková, Jiřina (advisor)
This thesis deals with still less expolited species of small fruit, evaluation of its physical and chemical parameters and proposal of a new soft drink from one of the studied species of furit. Firstly, for the characterisation of basic nutrition parameters (dry matter, content of organic acids and saccharides) and biologicaly active substances (vitamin C, anthocyanins and phenolic compounds) suitable titration, spectrophotometric, chromatographic and electrophoretic methods were chosen, optimized and validated. The sample preparation procedure was optimized as well. For three years (2010–2012) the content of listed parameters was monitored in some cultivars of five species of small fruit: in seven cultivars of sea buckthorn, in ten cultivars of cornelian cherry, in twelve cultivars of rowanberry, in two cultivars of chokeberry and in seventeen cultivars of elderberry. By means of Duncan’s test, analysis of principal components (PCA) and cluster analysis (CLU) the main differences between studied cultivars were observed mainly in sea buckthorn and rowanberry, where single cultivars were easily distinguishable from others on the basis of genetic origin. On the basis of comparison of determined parameters in studied species of fruit and with collaboration with fruit processing company the suitable species of fruit for commercial utilization was chosen – elderberry, as a important source of anthocyanins and phenolic compounds. A new soft drink as a proposal of utilization of this fruit was created – fruit juice or nectar with portion of elderberry juice. Mixed juices and nectars with various composition were prepared from elderberry and grape juice and the sensory analysis of these drinks was performed. The best evaluated were 100% fruit juices prepared with 30–50% portion of elderberry juice. The composition was jurally protected. On the basis of this protection the product consisted from 100% fruit juice with 10% of elderberry component mixed with apple and grape juice was introduced to the market by the fruit processing company.
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Determination of selected parameters in foreign beers
Punčochářová, Lenka ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
The aim of this thesis is determination of selected polyphenols, organic acids and elements (major and minor) in a foreign beers. Production of malt, beer production, beer types and beer styles are described in the theoretical part. Also analytical methods of beer analysis such as high performance liquid chromatography, iont chromatography and inductively coupled plasma optical emission spectrometry are described. The Experimental part deals with preparation of samples and calibration solutions, setting devices up and analysis of foreign beers samples. There were analyzed 14 foreign beers of which 11 samples were top-fermented beers, 3 samples were bottom-fermented. Four samples were produced in Belgium, three in England, three in Germany, two in the US, one in Holland and one in Poland. The results give an overview of the contents of compounds in foreign beers.
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Draft beer analysis by HPLC-ELSD and IC
Vanduchová, Petra ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
In this bachelor thesis is discussed the brewing process and composition of the beer. The experimental part deals with analysis of polyphenolic compounds and carbohydrates by HPLC, analysis of organic acids by the IC and the ICP-OES method was used for analysis of elements. The HPLC method was used to determine eleven polyphenols. Gallic acid was the most represented compound of polyphenols and quercetin was the least represented compound. Glucose, fructose and sucrose were analysed by HPLC and the most represented compound of carbohydrates was glucose. The ICP-OES method was used to determine ten elements. Zinc was the least represented element in the analysis and phosphorus and potassium were the most represented in the analysis.
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Monitoring of organic acid content in alcoholic drinks
Ostrihoňová, Katarína ; Běláková, Sylvie (referee) ; Benešová, Karolína (advisor)
The aim of the thesis is determination and optimization of organic acids in beers using the methods of capillary isotachophoresis (CITP) and high performance liquid chromatography with diode array detection (HPLC/UV). Beer is a complicated matrix therefore the samples need pretreatment using solid phase extraction (SPE). The diploma thesis discusses the optimization of the analytical methods (HPLC/UV and CITP) and optimization of SPE. In the theoretical part, history, characterization and technology of beer production are presented. Further, characteristics of organic acids and methods for organic acid determination are also discussed. The experimental part deals with the preparation of solutions, tested samples, calibration samples. Parameters and procedures of analytical methods (HPLC/UV and CITP) and pretreatment using the solid phase extraction are also described in the experimental part. All results are summarized and compared with the current literature in discussion and conclusion. Eleven beer samples from the retail stores were analyzed. In all samples, six organic acids (lactic, oxalic, succinic, acetic, citric, benzoic) were determined by CITP and five organic acids (lactic, oxalic, succinic, acetic, citric) by HPLC/UV were determined. Results of this study give an overview of the organic acid contents in beer samples.
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