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Factors affecting stability and consumer acceptance of sauerkraut water
Vašků, Barbora ; Mikulíková, Renata (referee) ; Márová, Ivana (advisor)
This diploma thesis is focused on the optimization of pasteurization of the cabbage juice in order to extend its shelf life. The theoretical part is focused on the description of the sauerkraut production technology and characterization of the main components of fermented cabbage and its juice, it also deals with pasteurization options and presence of probiotic strains. In the experimental part, the composition of the brine was analyzed from a chemical point of view (bioactive substances, sugars, carbohydrates), from a microbiological point of view (presence of probiotics, pathogenic organisms) and the effect of selected pasteurization processes on these components. Pasteurization at 90 °C for 0.5 minutes was determined as the most suitable treatment, during which potential pathogens are being eliminated, while most of the original bioactive components are preserved. After suggesting the effective pasteurization treatment, suitable species of genus Lactobacillus was selected to enrich the cabbage juice product because of decreasing of probiotics viability during pasteurization treatment. The strain Lactobacillus plantarum was determined as the most suitable probiotic species for cabbage juice enrichment, due its ability to survive in 2 weeks storage at 8 °C in cabbage juice. Chemical composition after 2 weeks of incubation with mentioned organism has changed. Quantity of lactic and acetic acid increased, while no changes in content of vitamin C were observed. Finally, sensory analysis was performed to evaluate suggested mixed fruit-vegetable drink. According to results of sensory analysis, the drink composed of cabbage juice and apple-beetroot juice in the ratio of 2:1 was found as the most acceptable.
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Different parameters monitoring by lager beer types
KLIMEŠOVÁ, Petra
This bachelor thesis focuses on beer and its production and emphasizes the possible ways of final technological treatments, especially filtration and pasteurization. The thesis is divided into two main parts - an introductory literature search, introducing the whole issue, and a methodology or a practical part. In the second part, the process of production of 11% Pilsner beer and its further procedures are described more in detail. The methodology includes the evaluation of data obtained during a ten-week observation of four different samples of bottom-fermented beers, all the Pilsner type. The data were obtained in two ways, specifically by analytical measurement using a beer analysis device - FermentoFlash - and by sensory analysis.
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Factors affecting stability and consumer acceptance of sauerkraut water
Vašků, Barbora ; Mikulíková, Renata (referee) ; Márová, Ivana (advisor)
This diploma thesis is focused on the optimization of pasteurization of the cabbage juice in order to extend its shelf life. The theoretical part is focused on the description of the sauerkraut production technology and characterization of the main components of fermented cabbage and its juice, it also deals with pasteurization options and presence of probiotic strains. In the experimental part, the composition of the brine was analyzed from a chemical point of view (bioactive substances, sugars, carbohydrates), from a microbiological point of view (presence of probiotics, pathogenic organisms) and the effect of selected pasteurization processes on these components. Pasteurization at 90 °C for 0.5 minutes was determined as the most suitable treatment, during which potential pathogens are being eliminated, while most of the original bioactive components are preserved. After suggesting the effective pasteurization treatment, suitable species of genus Lactobacillus was selected to enrich the cabbage juice product because of decreasing of probiotics viability during pasteurization treatment. The strain Lactobacillus plantarum was determined as the most suitable probiotic species for cabbage juice enrichment, due its ability to survive in 2 weeks storage at 8 °C in cabbage juice. Chemical composition after 2 weeks of incubation with mentioned organism has changed. Quantity of lactic and acetic acid increased, while no changes in content of vitamin C were observed. Finally, sensory analysis was performed to evaluate suggested mixed fruit-vegetable drink. According to results of sensory analysis, the drink composed of cabbage juice and apple-beetroot juice in the ratio of 2:1 was found as the most acceptable.
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Způsoby tepelného ošetření mléka a jeho dopady na nutriční jakost
Leischnerová, Zuzana
The topic of this bachelor thesis is "Ways of heat treatment of milk and its impacts on nutritional value". The theoretical part describes the composition of milk, its individual components and nutritional value. Other chapters focus on heat treatment, legislation concerning milk and differentiation of milk types based on intensity of treatment, individual treatments and their impact on the content and quality of individual components. At last there are described changes that occur in milk upon heating and reactions that may arise when exposed to high temperature. The nutritional value is generally lower than in raw milk, the changes are the most significant in sterilized milk, while the least change occur in the pasteurized milk. The practical part monitors the representation of individual types of milk on the market with respect to heat treatment and manufacturers. The questionnaire provides information from producers. The questionnaire shows that some manufacturers are already using ESL treatment in practice, but the term ESL is still not implemented in legislation.
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Alkaline phosphatase as an indicator for the heat treatment of the milk for cheesemaking
Malínská, Hana ; Potůčková, Miroslava (advisor) ; Lidmila, Lidmila (referee)
Alkaline phosphatase as an indicator for the heat treatment of the milk for cheesemaking
Summary
The aim of this diploma thesis was to summarize current knowledge about the evaluation of alkaline phosphatase activity as an indicator of heat treatment of milk for production of dairy products in theoretical part. In experimental part were comparised 2 methods for this enzyme activity determination, the original according to ČSN EN ISO 11816-2 (2003), using pasteurized milk as an extracting agent, and ISO 11816-2/IDF 155-2 (2010), using extraction buffer. For comparison were used 110 cheese samples, 8 quarg products, 49 fresh cheese products, 9 spiced fresh cheese products, 7 white-brined cheese products, 7 Penicillium sp. flora cheese products, 5 coryneform flora cheese products and 25 semi-hard and hard cheese products.
Alkaline phosphatase (EC 3.1.3.1) is a hydrolase cleaving phosphate groups at the 5th and 3rdposition of many molecules including especially nucleotides and proteins. The enzyme has a pH optimum in the alkaline range (pH 10), their cofactors are ions Zn2+and inhibitors Cu2+. Dairy alkaline phosphatase derived from mammary epithelium and other cellular residua in milk. In this medium is the enzyme localized on the membrane of fat globules. Their amount depends on the stage of lactation (the highest concentration is in colostrum) and animal health (their concentration increases when disease, especially mastitis, starts). Due to its specific thermostability is alkaline phosphatase used for proof of milk and milk products pasteurization.
In the experimental part of the diploma thesis was found that the recommended substitution of pasteurized milk for buffer improves enzyme extraction process from cheese matrix and so enhances method sensitivity (p > 0.05). Method unsuitability for Penicillium sp. flora cheese (especially for blue-veined ones) was also confirmed (p > 0.05). This unsuitability could be explained by content of microbial alkaline phosphatase. For the same reason might not be this method suitable also for coryneform flora cheese. On the contrary, this analysis is suitable (p > 0.05) for white-brined cheese. For spiced fresh cheese were the results in terms of evaluation suitability ambiguous. Based on the obtained data was also confirmed the suitability of proposed limit (10 mU/g) for residual enzyme activity in products from pasteurized milk.
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Microbiology of unfiltered beers from craft breweries and the possibility of shelf life extending
Janíková, Jolana ; Rada, Vojtěch (advisor) ; Chládek, Ladislav (referee)
In the last ten years can be recorded a multiple number of minibreweries, called sometimes craft breweries I tis not caused only by demand of kinds of beer characterised by special types of beer styles, but as well by the fact, that they are not anyway regulated
and keep their natural taste and smell. The problém of unregulated (unfiltered
and unpasteurized) beers starts by the contamination during their production and it may cause their relatively fast spoiling. Shelf life of these beers is e few weeks only. The time of their minimal shelf life is influenced by a lot of factors content of alcohol, rest extract
and mentioned extent of contamination. The breweries called as industrial or commercional treat their beers by pasteurization or filtration which cause inactivation or killing of the microorganisms or their elimination. These beers are microbiologically stabile, they are not liable to quick spiling and i tis possible to insure their longer shelf life. Pasteurized a filterd beers show changes in their sensorial character.
The aim of this diploma thesis was to determinate the condition of flash pasteurization of unfiltered beers with the aim of microbiological stability and simultaneously no changes
of their sensorial quality. The experiment is finally in treatment unfiltered beer by differnt dosing of pasteurization units and following microbiological analysis, able to demonstrate
the stability effect. The analysis were used with unfiltered and unpasteurized beers
and with unfiltered beers where the pasteurization doses 20 PU, 30 PU, 40 PU, 60 PU, 80 PU and 100 PU were used. The idividual parameters were watched within the horizont
of 4 months. The part of these tests was even microbiological analysis of the rinse water.
Another task was to find out the dates from the microbiological controls of beer
in selected small breweries, which use in order to heighten of microbiological stability, different kinds of filtration, to verify their effectivity and to appreciate their acceptability
for minibreweries.
The test showed the effectiveness of pasteurization of unfiltered beer with the rations 40 PU minimally. Where higher ratins were used could be seen apparent sensorial changes. The pasteurization of unfiltered beers are for craft breweries useful only in case of higher production of bottled beer or beer for export, because the financial expenses bound
with provision flash pasteurizer are to big and for minibreweries mostly limiting.
The kieselguhr filtration as well the ultrafiltration are for minibreweries unusefull, as they could not be able to insure such conditions that provide their proper affectiveness.
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Heat treatment of milk and its importance
VOČADLOVÁ, Kateřina
The aim of this work is to assess the public knowledge of heat treatment, its purpose and effect on milk quality and to find out their attitude to raw milk consumption. Heat treatment of milk is a commonly used part of dairy processing. Although the heat treatment has a significant impact on ensuring microbial quality, safety and shelf life of milk, its application still face a public disagreement, primary in connection with potential health benefits, which are lost during heat treatment. The survey took place (from November 2015 to February 2016) in a randomly selected group of respondents (n=265). It was found that 22 % of respondents buy raw (unpasteurized) milk and only 27 % of them reported pasteurizing of the milk before consumption. 68 % of respondents just cool the milk down and consume it without any thermal treatment. 23 % of respondents though that pasteurization has negative effects on milk quality and 21 % of respondents said that consumption of milk pose no health risk.
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Hodnocení kvalitativních ukazatelů mléka
Vintrlíková, Eva
This Master's thesis is focused on evaluation of qualitative characters of cow's, sheep's and goat's milk and its different sensory quality. The theoretical part describes in detail every characters of milk as a fat, proteins, carbohydrates and also will focused on extension of quality of milk using thermo-adjustment and focused on basic sensory evaluation of certain characters, including the most frequent deviations from standard state. In the practical part is summary of results from sensory evaluation of many varieties of milk with different thermo-adjustment or following thermo-adjustment in households consecutive years 2010--2013.
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