National Repository of Grey Literature 78 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Production and characterization of biochar from mixed plant waste
Bureš, Vojtěch ; Nábělek, Jakub (referee) ; Pořízka, Jaromír (advisor)
This work focused on biochar production from mixed vegetable waste in the context of home gardens and small farms. The aim of the work was to produce different types of biochar from common mixed garden waste material and then to characterize it according to the European Biochar Certificate (EBC) classification, as well as to develop a methodology for household biochar production, according to current knowledge. Four of the five biochar samples produced met all the criteria for the EBC-Feed category and are therefore suitable for any form of use, including animal feed production. The last sample did not meet the EBC parameters for usable biochar due to above-limit levels of polycyclic aromatic hydrocarbons (PAHs), but according to current studies and the new European Union limit values for fertilisers and amendments, the detected PAHs concentrations do not prevent its application to agricultural land. Therefore, based on the findings of this work, it is possible to recommend domestic production of biochar and its application to agricultural soils for long-term improvement of soil quality.
Monitoring of inorganic contaminants in moravian white wines
Šebek, Richard ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis is focused on monitoring of selected inorganic contaminants, especially metallic elements and macro elements, in Moravian white wines. The aim of this thesis is to compare the element composition of wines according to the geographical origin, different production system and vine varieties. Two spectrometric techniques were used for elemental analysis of wine samples: Inductively coupled plasma with mass spectrometer and inductively coupled plasma with optical spectrometer (ICP–MS and ICP–OES). Evaluation of the results was carried out using statistical method of variance analysis (ANOVA). Vanadium, copper, lead and magnesium were evaluated as statistically significant in at least one Moravian sub-region. No statistically significant results were found in other comparisons.
Study of protein isolates digestibility
Čulíková, Andrea ; Juglová, Zuzana (referee) ; Pořízka, Jaromír (advisor)
Proteins are the structural components of all tissues of the human body. They are biopolymers that consist of amino acids. According to their origin, proteins are divided into plant and animal proteins. In the bachelor thesis, the properties of proteins isolated from wheat bran and commercial protein isolates from different plant and animal sources are discussed. Among the plant proteins, soy, almond, sunflower, chia and rice proteins were studied. Of the animal proteins, beef and whey proteins, among the most popular on the market, were studied. Specifically, the bachelor thesis deals with protein isolates, their composition, extraction methods by which protein isolates can be obtained from sources and subsequently their digestibility. The digestibility of protein isolates is one of the nutritional parameters that determines how well our body can utilize a given protein. In the experiments part, methods for the determination of protein content and digestibility in protein isolate samples were described. The Kjeldahl method was used to determine the protein content of the samples, and the results were then compared with the protein content indicated on the packaging. The enzymatic digestion process was simulated, the residue was subsequently lyophilized, and the digestibility of the protein isolate samples was studied gravimetrically. The results showed that whey protein was the best source of protein with respect to digestibility, with a PDCAAS value of 96.8% and a PDCAAS value of 0.94.
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.
Use of antioxidants in the production of white sausages
Richterová, Nikola ; Pořízka, Jaromír (referee) ; Mikulíková, Renata (advisor)
This thesis focuses on the use of antioxidants in the production of white sausage. Two herbs were chosen as representatives of natural antioxidants (Salvia officinalis and Rosmarinus officinalis), whose effects were compared with the synthetic antioxidant butylhydroxytoluene. Furthermore, this thesis discusses the possibilities of using the FoodScan 2 device for the determination of basic nutritional characteristics in the produced sausages. The impact of antioxidant addition was evaluated, especially on the sensory quality and consumer acceptability of the manufactured sausage. Herbs were added to the sausages in dried, ground form and in the form of prepared ethanol extracts. The impact on the oxidative damage of the sausages during storage in cold (4 °C) for five days was also examined. The protein, fat, water, and ash content in the sausage samples was determined using the FoodScan 2 device, the results were compared with those acquired using simple analytical methods. On the day of production and then five days of storage in cold, the lipid content and fatty acid profile in the sausage samples were examined by gas chromatography, and the content of substances reactive with thiobarbituric acid in the sausage samples was examined by spectrophotometric analysis. The antioxidant activity of the samples was also measured. Furthermore, the manufactured sausage samples were subjected to microbial control. The prepared ethanol extracts and butylated hydroxytoluene were analysed for antimicrobial activity against Escherichia coli and Micrococcus luteus. For most evaluators, the herbs and their extracts that were added to the meat product appeared tasty and consumer friendly. Statistically significant differences were found between the samples using the Kruskal-Wallis test. In produced samples, herbs exhibit comparable efficiency to synthetic butylhydroxytoluene and could be a suitable alternative to synthetic food additives.
Optimization of the production of yogurt with increased protein content from wheat bran
Adamczyková, Michaela ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
This thesis deals with the use of wheat bran in the form of protein isolate as an additive in the food industry, optimalization of the formula of fortified yoghurts and the encapsulation of plant proteins, used as a method to mask the negative sensory properties of products with the addition of these proteins. The theoretical part deals with the characterization of fermented milk products, wheat bran as a source of protein and the possibilities of masking the negative sensory properties of protein isolates. The produced yoghurts were sensory evaluated and their nutritional and technological properties were analyzed in the experimental part. By sensory analysis of yoghurts made from different types of milk, full-fat UHT milk was determined to be the best for the production of fortified yoghurts. Yoghurts prepared from this milk were fortified with wheat bran protein isolate. The products thus had an increased nutritional value, but their sensory values deteriorated. The yoghurts had a gritty feel, which was subsequently mitigated by grinding the protein isolate to finer parts. The formula for the production of fortified yoghurts was optimized by the addition of alternative protein, which had a positive effect especially for yoghurts with a 10% protein content. Yoghurts with protein isolate were evaluated with a negative score for the bitter taste parameter. Encapsulation of proteins significantly reduced the intensity of the bitter taste. Synergy of all prepared samples was determined by filtration. Yoghurt from full-fat UHT milk showed a syneresis of 31.76 ml per 100 g of yoghurt. The addition of protein led to a change in the synergy of this yoghurt. From the rheological analysis, it was determined that 10% yoghurt with encapsulated particles had a higher value of dynamic viscosity and yield stress. Sensory analysis data were evaluated using principal component analysis.
Selection of suitable disinfections to prevent the spread of Corynebacterium pseudotuberculosis in farms focused on the production of milk products and meat
Liová, Alexandra ; Pořízka, Jaromír (referee) ; Marková,, Jiřina (advisor)
This diploma thesis deals with the selection of suitable disinfectants and their effective concentrations for the prevention of the spread of the causative agent of caseous lymphadenitis in sheep and goat farms with a focus on milk processing, dairy and cheese production or meat production. For these purposes, disinfectants were selected from the group of quaternary ammonium compounds, oxidizing compounds, biguanides and alcohols, which were tested according to the ČSN EN 1656 standard on Corynebacterium pseudotuberculosis isolates forming a biofilm. The theoretical part first deals with the general characterization of the bacterial species Corynebacterium pseudotuberculosis and caseous lymphadenitis. In other chapters, the bacterial biofilm, its formation and the factors that influence it are described. Last but not least, the theoretical part is focused not only on the legislative treatment of the use or testing of disinfectants, but also on the closer characterization of their individual groups. In the experimental part, the procedure for determining the sensitivity of Corynebacterium pseudotuberculosis biofilms to selected disinfectants (benzalkonium chloride, chlorhexidine digluconate, ethanol, iodinated povidone, sodium hypochlorite and peracetic acid) was first optimized according to the ČSN EN 1656 standard. The optimization was followed by the cultivation and formation of biofilms of Corynebacterium pseudotuberculosis and the evaluation of their intensity by spectrophotometric determination of optical density. Subsequently, tested disinfectants were applied to the obtained biofilms, and after 24 hours of incubation from the end of the disinfection process, the effectiveness of the tested disinfectants was visually evaluated. At the end of the research, the minimum bactericidal concentrations for individual disinfectants were determined and the concentrations of these substances suitable for preventing and preventing the spread of the bacterium Corynebacterium pseudotuberculosis in small ruminant farms were also selected.
Optimization of fresh cheese production and their characterization
Bittnerová, Eva ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This thesis deals with the optimization of fresh cheese production and their characterization in terms of free and bound fatty acids, volatile (aromatic) substances and sensory quality. The theoretical part deals with the characterization of fresh cheeses, their production technology and sensory quality. It also includes options for determining volatile substances and fatty acids in fresh cheeses. In the experimental part, produced fresh cheese samples were analyzed during 14-day storage. The fat was extracted from fresh cheeses with a mixture of diethyl ether and petroleum ether, fatty acids were converted to the appropriate methyl esters by acid esterification with boron trifluoride as a catalyst and determined by gas chromatography with a flame ionization detector. Volatile substances were identified based on the comparison of mass spectra with a library of spectra and retention indices (according to Van den Dool and Kratz). The content of the identified substances was expressed semi-quantitatively using the areas of the respective peaks. A total of 20 fatty acids were identified, palmitic, myristic, stearic, capric, caproic and lauric acids predominated as representatives of saturated fatty acids, oleic acid as a representative of monounsaturated fatty acids, and linoleic acid was abundantly represented among polyunsaturated fatty acids. In terms of volatile substances, a total of 37 compounds were identified in the frozen samples and 42 compounds in the fresh samples. Alcohols, acids, aldehydes and ketones were the most represented. The results of the sensory evaluation show that the evaluators liked the stored cheeses better, so the cheeses maintain a good quality of min. for 14 days when stored in the refrigerator.
Development and characterization of new dairy products with increased fiber and protein content
Smatana, Igor ; Punčochářová, Lenka (referee) ; Pořízka, Jaromír (advisor)
The bachelor thesis was focused on the production and characterization of new dairy products with increased protein and fiber content. Ground wheat bran was used as the fiber source and wheat bran protein extract was used as the protein source. From an ecological point of view, it would be ideal if 100% of the raw material was used and nothing was left as waste. We tried to approach this by using the waste (by-product) that arises during the production of flour as an additive to dairy products. The theoretical part focused on the characterization of fermented and unfermented dairy products and their production, the nutritional value of proteins and fiber and the composition and benefits for human health of wheat bran, protein isolation from wheat bran and common analytical methods to determine rheological properties, viable cell numbers. water binding and sensory acceptability. Two basic dairy products were created, one fermented and one unfermented, and subsequently fortified with a source of fiber (wheat bran) and a source of protein (protein concentrate from wheat bran). All products were subsequently characterized for characterization. Water binding, rheological and sensory properties were determined. The fermented dairy product was also subjected to cytometric analysis to determine the number of viable cells. The experimental part describes the methods we use to prepare and characterize new products. After evaluating the measured data, options for optimizing the acceptability of products by consumers were proposed. The results showed that the organoleptic properties were negatively affected by the addition of wheat bran and protein concentrate.

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