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Study of yogurt composition in process of its preparation
Fajtl, Zbyněk ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
This thesis deals with the study of yogurt preparation and changes during its storage. The theoretical part contains information about parameters affecting both the preparation and properties of the final product. The experimental part describes methods and procedures used for determination of critical parameters such as lactic acid, lactose, glucose and galactose concentrations (HPLC-RI), amounts of streptococci and lactobacilli. The data was graphically evaluated and commented on. The work also included sensory analysis in which the prepared yogurt was compared with commercially available products. The results of this work can serve both consumers and smaller yogurt producers.
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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.
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The effect of nutritionally desirable ingredients on selected sensory properties of dairy products
HRADILOVÁ, Kristina
The aim of this Master's thesis was to assess the chemical composition and selected properties of cheeses and yogurts, to which various amounts of skimmed milk powder (SMP) were added. The literature review discusses the characteristics and division of cheeses and yogurts, their nutritional significance, rheology and its changes after the addition of proteins. In the experimental part of the thesis, the chemical composition of yogurts and cheeses was determined by spectrophotometry. Further, other laboratory methods were used to determine their acidity, viscosity, colour and hardness. Our research has shown that there are correlations between SMP content and the protein, fat, lactose and dry matter in yogurts and cheeses, between SMP content and the hardness, acidity and colour of cheeses, and between SMP content and the acidity and viscosity of yogurts. The results of this work enable determining the ideal amount of SMP to cheeses and yogurts in order to improve their nutritional and sensory properties.
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Dairy products in human nutrition, labelling according to czech legislation; consumer information and preferences
Dovolová, Barbora ; Kudlová, Eva (advisor) ; Dostálová, Jana (referee)
This bachelor thesis evaluates the dairy products labelling in the Czech Republic based on the requirements of the Czech legislation. It also pursues consumer's taste preferences, their interest and awareness of the dairy products labelling. The theoretical section mentions the history of dairying and the importance of milk products in human nutrition. The following chapters present individual dairy products and it described their production, labeling and division into kinds. The practical section reveals that the dairy products are labeled in accordance with the Czech legislation. The results are presented in the form of photos and tables (mini photobook). This part also examines whether the adult people interest in the dairy product labeling, how to orient in a range of dairy products and which products they prefer. The product evaluation was carried out in two big stores in Jablonec nad Nisou by using photographs. It was found that majority of companies indicates their milk products correctly. Identified deviations were discovered in the labelling of nutrition declaration or allergens. This is a relatively new requirements but very important. The questionnaire was found that 68 percent of people read informations on dairy products voluntarily. Most of the respondents consume especially milk, yoghurts and...
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Study of yogurt composition in process of its preparation
Fajtl, Zbyněk ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
This thesis deals with the study of yogurt preparation and changes during its storage. The theoretical part contains information about parameters affecting both the preparation and properties of the final product. The experimental part describes methods and procedures used for determination of critical parameters such as lactic acid, lactose, glucose and galactose concentrations (HPLC-RI), amounts of streptococci and lactobacilli. The data was graphically evaluated and commented on. The work also included sensory analysis in which the prepared yogurt was compared with commercially available products. The results of this work can serve both consumers and smaller yogurt producers.
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Fatty acid composition of bovine milk and milk products
MAŠKOVÁ, Gabriela
The thesis deals with changes in proportion of fatty acids in bovine milk. The aim of this study was to assess the profile of fatty acids in milk and subsequently in yoghurt produced from it. The thesis also evaluates the influence of breeding management, breed as well as region. The results of the thesis confirmed that processing of milk into yoghurt has little to no effect on fatty acids profile and proportion of fatty acids is stable. Processing milk into yoghurt alters nutritional value of the product only minimally and the changes in fatty acids profile are not statistically relevant. Profile of fatty acids in the end product was mostly influenced by breeding management, where nutritionally most valuable milk and therefore yoghurt comes from grazing dairy cows. Breed itself has influence more over content of main elements, such as fat or protein content, in milk rather than over fatty acids profile. Influence of region tightly relates to breeding management where in highlands pasturing is more common and in lowlands it is more common to have dairy cows in stables.
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Dairy products in human nutrition, labelling according to czech legislation; consumer information and preferences
Dovolová, Barbora ; Kudlová, Eva (advisor) ; Dostálová, Jana (referee)
This bachelor thesis evaluates the dairy products labelling in the Czech Republic based on the requirements of the Czech legislation. It also pursues consumer's taste preferences, their interest and awareness of the dairy products labelling. The theoretical section mentions the history of dairying and the importance of milk products in human nutrition. The following chapters present individual dairy products and it described their production, labeling and division into kinds. The practical section reveals that the dairy products are labeled in accordance with the Czech legislation. The results are presented in the form of photos and tables (mini photobook). This part also examines whether the adult people interest in the dairy product labeling, how to orient in a range of dairy products and which products they prefer. The product evaluation was carried out in two big stores in Jablonec nad Nisou by using photographs. It was found that majority of companies indicates their milk products correctly. Identified deviations were discovered in the labelling of nutrition declaration or allergens. This is a relatively new requirements but very important. The questionnaire was found that 68 percent of people read informations on dairy products voluntarily. Most of the respondents consume especially milk, yoghurts and...
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Fatty acid composition of caprine milk and milk products
PECOVÁ, Lenka
Changes occur in milk during the technological processing of raw milk, which also affect the properties of milk fat. Dairy products may have different properties compared to the raw milk. Chemical and microbial processes can alter the presence and distribution of individual fatty acids and thus influence the nutritional value of the product. The aim of this thesis was to assess the presence of fatty acids in milk fat of goat milk and to evaluate differences in the spectrum of fatty acids in goat milk and yoghurt produced from it.
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Viscosity and acidity of selected type of natural yoghur
BÁRTOVÁ, Zuzana
The aim of the thesis was to evaluate the acidity and viscosity of natural yoghurt depending on the different addition of skimmed milk powder and using of the methods of sensory analysis to evaluate the perception of these properties by young consumers. Part of this work was to analyse acidity and viscozity in selected kinds of natural yoghurts purchased in the market network of the Czech Republic (CR). The literature search mentions basic characteristic of yoghurts and their classification, acidity and rheological properities of yoghurts including the factors, which affect them and sensory analysis. In the experimental part of the study the acidity value, total solids and viscosity measurements were detected by physico-chemical analyses of samples of natural yoghurts. At samples of yoghurts with different content of skimmed milk powder the sensory evaluation was also subjected and the graphs of sensory profile were compiled. The observed results showed, that from the samples of yoghurts made in the laboratory was the most satisfactory sample containing 10 % of skimmed milk powder. At samples purchased in the market network of CR were detected very low leveles of titratable acidity.
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