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Monitoring of selected metals in comercial bio wines
Bortlová, Alžběta ; Reichstädter, Marek (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis is focused on monitoring of selected metals in commercial organic wines. The aim of this thesis was to compare element content of organically produced wines with wines originating from other agrotechnical production system. Optical emission spectrometry with inductively coupled plasma (ICP-OES) was used for element analysis of wine. Statistical method analysis of variance has been used to assess whether the concentrations of the elements showed statistical differences between wines originating from organic production and wines originating from other production systems. Statistical differences were found in 3 of 20 analysed elements. Correlations between the element analysis and type of production system of grapevine were observed in content of the zinc, nickel and manganese.
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Sensory evaluation of drinks enriched with extracts of herbs
Scholzová, Kristýna ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with sensory evaluation of herbal non-alcoholic beverages, being a part of a new product development. The theoretical part provides information concerning chemical composition, health effects, food applications and aroma compounds of the herbs of interest (peppermint (Mentha piperita), sage (Salvia officinalis), St. John’s wort (Hypericum perforatum) and lemon balm (Melissa officinalis). Another topic is a description of sensory methods, requirements and arrangement of the analysis, statistical methods, and also technological processes leading to herbal syrups and beverages production. The practical part comprises sensory analysis of a few, newly designed, formulas of one-component and two-component alcohol free herbal beverages. The sensory panel consisted of 40 students of master's and also doctoral study programme at Faculty of chemistry, University of Technology Brno. Four subsequent experiments are introduced, each of them consisting of a few sensory tests and including corresponding sensory forms attached. The sensory tests arrangement was based on currently valid Czech Technical Standards, using a ranking, descriptive, paired comparison, sensory profile testing and scaling methods. For the purpose of statistical evaluation, Friedman, Kruskal-Wallis, PCA and Faktor analysis were used. Level of abilities and sensory experience of panelists were found comparable to consumer testing. The results include sensory characteristics of all of the beverages tested. In general, the one-component beverages were preferred to the two-component beverages and the additive colouring with aronia concentrate wasn´t found any benefitial, from the sensory point of view. The consumer questionnaire proved all of the samples to be very promising, but based on the sensory results, we would consider the mint and the sage-mint beverages being the most potentialy applicable samples.
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Influence of the filtration and pasterurization on content of selected vitamins in beer
Šimíčková, Adéla ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This master thesis focuses on the influence of the filtration and the pasteurization on the content of the selected vitamins in beer. Specifically, the vitamin B2, B3, B6, B9 and B12. The high performance liquid chromatography with diode array detector was used as a separation method for the vitamin content analysis. First this method was optimized and then validated. The data obtained by analyzing 28 beer samples were evaluated using a statistical method – the analysis of variance. This method provided parameters P, F and Fcrit which are important for the assessment of the statistically significant differences between the individual groups of beer . Based on these parameters, a significant effect of the filtration was observed for the vitamin B2 and B3. The filtration has reduced the amount of the vitamin B2 while it increased the concentration of the vitamin B3. The pasteurization had no significant effect on the vitamin content.
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Study of the chemical processes during kombucha technology
Chludilová, Markéta ; Obruča, Stanislav (referee) ; Pořízka, Jaromír (advisor)
The kombucha drink is referred to as leavened tea with added sponge called a scobie. In this way, a low-alcohol beverage is obtained, which gains considerable popularity, especially due to the alleged beneficial properties for human health. The microbial composition of this beverage is very rich, consisting of bacteria and yeasts living in a beneficial symbiosis [11]. The microbial composition of the drink and its beneficial effects on human health are very closely related. This work deals with the analysis of the chemical composition of the commodity beverage, especially with regard to the content of major components such as organic acids, carbohydrates and ethanol. These analytes are among the most common and most profoundly found substances in the carbohydrate beverage and are very closely related to the microbial composition of the scoby itself [3]. Combo beverage samples were supplied by RebornFood, one of which is the commercial production of this drink on the Czech market. At the same time, this company bases itself on purely natural fermentation of beverages, and therefore it is not particularly involved in the production process. The results of this diploma work point to the effect of the scoby used and the associated occurrence of analytes in the beverage, as well as the production process associated with the formation of analytes, which is described in several articles. It is expected that this work will provide information both on the production conditions and on the chemical properties of the beverage related to the condition of the scoby, which will be used further, both for RebornFood and the material used to solve the technical problems of this beverage production.
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Adsorption of toxic metals from wastewater to waste material from the food industry
Křikala, Jakub ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This thesis was focused on the possibility of secondary utilization of waste material from the wine industry to remove heavy metals from wastewater. In the theoretical part, there were discussed mainly the problems of heavy metals pollution including methods of their removal and ICP-OES detection. Furthermore, the waste material from the wine production and the possibilities of its further processing were discussed there. The primary objective of the experimental part was to characterize the material by IR analysis, optimization of adsorption conditions, isotherms construction and determination of maximum adsorption capacities of white, red and chemically modified marc for Cd, Cr, Cu, Ni and Pb. From the parameters influencing the adsorption efficiency, the adsorbent load was optimized (m/V ratio = 0,02); pH values found were 5 for Cd, Cu, Ni, Pb and 3 for Cr and the contact time to reach the equilibrium was 15 minutes for Cd, Ni, Pb and 30 minutes for Cr and Cu. Maximum adsorption capacity for heavy metals were calculated from adsorption isotherms by applying the Langmuir model and found to be 18,829 7 mg/g for Cd; 10,664 7 mg/g for Ni; 35,602 0 mg/g for Pb (modified marc with 1M NaOH); 4,678 4 mg/g for Cu and 9,629 0 mg/g for Cr. The results of the work confirm the good adsorption potential of heavy metals on marc and the positive effect of chemical modification of natural biosorbents to improve their adsorption capacity.
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Influence of the chicken breeding method on the selected chemical constituents of chicken eggs
Michalec, Adam ; Vespalcová, Milena (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis is focused on the analysis of egg yolks and egg whites from chickens raised with different breeding methods in the Czech Republic using three analytical methods. The Kjeldahl method was used to determine the proteins, the Soxhlet method was used to determine the lipids and ICP-OES was used for elemental analysis. The theoretical part describes the history of chicken breeding, marking and distribution of eggs and composition of eggs based on various aspects. The main point was the separation of egg yolk and egg white and the subsequent description on the chemical and physiological level. Principle of used methods is also described. The experimental part deals with the preparation of samples, calibration samples and process analysis. All the results of analysed substances are summarized, statistically evaluated and compared with the other literature. For this analysis were used eleven different types of eggs from the Czech Republic from six different categories.
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Extraction of anthocyanin pigments from elderberries pomace
Lošková, Tereza ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis deals with the production of the concentrate from the Elderberry marc extract (Sambucus nigra L.). The basic chemical characteristics in this concentrate were determined. The theoretical part of the thesis deal with the botanic characteristic of the Elderberry and its berries. The characteristic of the phenolic compounds, mainly anhocyanins was summarized. The use of the anthocyanin pigments in the food industry, the possibilities of their extraction and the concentrate production was discussed. Thereafter the methods of the anthocyanin content and the phenolic content determination were described. In the experimental part of study, the production of the anthocyanin rich extract from Elderberry marc was optimized. The extraction of the marc by the 1:1 ethanol/water (V/V) solvent with the ratio marc/solvent 1:2 (w/V) showed the most convenient. The production of the concentrate followed. During the concentration on the rotary evaporator the pigment degradation was investigated. The degradation decreased with the decrease of the temperature. The final concentrate was prepared from the extract on the rotary evaporator by 45 °C for 15 minutes. This product had the 7times lower volume compared to the initial extract. In the final concentrate come of the chemical characteristic were determined. By liquid chromatography (HPLC) the major pigments cyanidin-3-sambubiosid and cyanidin-3-glucosid were determined. Their total content was determined to 34,9 gl-1. The total anthocyanin content was determined by pH differential method to 7,1 gl-1 (expressed as cyanidin-3-glucoside equivalent). The total phenolic content was determined to 27,1 gl-1 (expressed as gallic acid equivalent) by Folin-Ciocalteu method. By electron paramagnetic resonance the increase in antioxidant activity with the increase in concentration was found. Up to 42 aromatic compounds was determined in Elderberry marc, its extract and the final concentrate.
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Extraction of bioactive substances from the pomace of red grapes
Jandrtová, Sabina ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the research of chosen chemical characteristics in juice and in extracts of grapevine (Vitis vinifera L.). The theoretical part is divided into three parts. In the first part is described the botanical characteristic of grapevine, then its origin, morphology, chemical composition, species and uses. In the second part are characterized anthocyanin pigments, their occurrence and attributes. There are described methods of the investigation. In the third part are described extractions. The experimental part illustrates extractions of the pomace. The purpose of these extractions is to find out the total amount of anthocyanins and phenolics in the pomace, and which solvent gives the highest yield. Then the chemical characteristics, such as total and soluble solids, pH, the amount of titratable acids, reducing carbohydrates, phenolics and anthocyanins, are described in this section. All determinations are executed and results are compared among grapevine juice and two species (Cabernet Sauvignon and Zweigeltrebe). The most suitable solvent is selected a mixture of water and ethanol in a ratio 50:50. In the most effective hours are determined the chemical characteristics. The titratable acids are expressed as the amount of the tartaric acid. The amount of phenolics is expressed as gallic acid and the amount of anthocyanins as malvidin-3-glucoside.
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Chemical characteristics of fruit Mirabelle plum
Lukšová, Leona ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with chemical and physical analysis of dried, lyophilized and stewed fruit, specially Mirabelle de Nancy. Theoretical part is devoted to the origin, the economic importance of plums, the botanical classification of Mirabelle de Nancy and other subspecies belonging to the genus Prunus. Subsequently the most economical method of preserving food called lyophilization is described. Part of this work is also the theme of raw food and description of biologically active substances contained in this fruit. In the experimental part, these characteristics of Mirabelle de Nancy were analyzed: total solids, soluble solids, determination of reducing sugars, titratable acidity, phenolic substances and ascorbic acid. It has been found that the lyophilized friut contains 16,8 wt. % of reducing sugars which is less than dried fruit with a value of 18,0; wt. %. It also contains less titratable acids with a value of 59,7 mmol/l versus 72,7 mmol/l in dried fruit.
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