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Classic vs. traditional bulgarian yogurt - chemical, microbiological and sensory characterization
Jasimová, Zahraa ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the production and characterization of yogurt. In total, three types of yogurt were produced: "classic" white yogurt, Bulgarian yogurt made from commercial culture, and traditional Bulgarian yogurt obtained by inoculation of yogurt brought from Bulgaria. The products were characterized in terms of sensory quality, volatile profile (HS-SPME-GC-MS), and microbial profile (qPCR). The aim was to find out whether and how the mentioned samples differ in terms of the mentioned parameters. In the theoretical part, Bulgarian yogurt and its method of production technology are characterized. Sensory quality, the possibilities of sensory evaluation of yogurts, the determination of the presence of volatile substances, and the method of their determination are also mentioned. In the last chapter of the theoretical part, the microbial profile is characterized, the possibilities of identifying microbial cultures, and finally the nutritional value of yogurts is described. In the experimental part, the production process of Bulgarian yogurt samples was first optimized, and these were subsequently compared with "classic" white yogurt. For sensory evaluation, graphic scales were used to evaluate appearance, color, consistency, aroma, and taste, as well as a profile test (sweet, sour, bitter, yeasty, and possibly other tastes) and an ordinal test. The results show that the Bulgarian yogurts were assessed sensorially worse than the classic yogurt, mainly because of the sour taste. Samples of Bulgarian yogurts also showed a yeasty taste, the presence of yeast was confirmed using the qPCR method. The profile of volatile (aromatic) substances in the samples was determined using the HS-SPME-GC-MS method. A total of 24 volatile substances were identified in all yogurt samples, of which 6 alcohols, 2 esters, 6 acids, 7 carbonyl compounds, 3 and sulfur compounds.
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Iodine content in milk and milk produkts
DAVIDOVÁ, Lucie
The subject of the dissertation was to find out and evaluate the iodine content in milk products in a distribution network in the Czech Republic. The dissertation brings update information about the iodine content in consumer milk and white yogurt which are a common part of alimentation for the majority of human population. Sampling was carried out in a sale network during 2007 and 2008. Altogether, 43 samplers of consumer milk and 59 samplers of white yogurt were taken. The iodine content in products was determined with colometric method by Sandell-Kolthoff. The average iodine content in consumer milk in 2007 was 300,5 {$\mu$}g {$\bullet$} l-1 and 310,2 {$\mu$}g {$\bullet$} l-1 in 2008. The maximal iodine content in milk reached the level of 404,8 {$\mu$}g {$\bullet$} l-1 (2007) and 732,0 {$\mu$}g {$\bullet$} l-1 (2008). The lowest level of iodine content in white yogurt in 2007 was at the level of 406,0 {$\mu$}g {$\bullet$} kg-1 and 422,7 {$\mu$}g {$\bullet$} kg-1 in 2008. Comparing years 2005 and 2006 there was recorded a slight decrease at these products. Some differences were recorded at different milk product producers and as well as the season has got a considerable influence. If the overall average milk and milk products consumption makes 0,64 litre per person then the daily recomended portion is covered by 130 per cent.
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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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Vliv obalů a etiket na nákupní chování spotřebitelů na trhu s jogurty
Doležalová, Markéta
DOLEŽALOVÁ, M. The influence of packaging and label on consumer´ purchasing behaviour on the youghurt market. 2017. 111 s. Master thesis. Brno: Mendel University, Faculty of Business and Economics. Thesis supervisor: Ing. Veronika Antošová, Ph.D. The master thesis deals with consumer behaviour of young people (students aged 20 to 25) on the youghurt market. Emphasis is placed on the impact of packaging and labels in the use of marketing research, especially eyetracking observations and in-depth interviews. The output of the thesis is a draft recommendation for packaging and labeling in this sector.
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Mýty týkající se nutriční kvality mléka a mléčných výrobků
Procházková, Martina
The aim of this bachelor´s thesis is to provide an overview of basic information clarifying the myths regarding the nutritional quality of milk and dairy products, specifically yogurt and processed cheese. The work evaluates the composition of fresh and shelf-stable milk, and supports the fact that fresh milk is healthier than shelf-stable milk is an incorrect assumption. Thesis is focused on the wrong conjecture that milk is inappropiate for human health, but on the contrary milk together with dairy products are source of valuable and beneficial nutrients for human body. In conclusion, the thesis is pointing out and explaining issues of live and active cultures, probiotics in yoghurts, yoghurt additives and the raw materials and ingredients that are needed in production of processed cheese including food additives (AFCAs).
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Vliv obsahu tuku a sušiny na reologické vlastnosti bílých jogurtů
Kužmová, Barbora
The thesis is aimed at monitoring the effect of fat and dry matter on rheological properties of white yogurts. The theoretical part describes the milk and milk products with a focus on yogurt, its production, composition and nutritional value. A review of literature continues with physical and mechanical properties of the fluids, rheological properties, viscosity and its measurement. The practical part aims to evaluate selected yogurt samples, to determine their density, viscosity, shear stress depending on shear rate and the time and temperature dependence of viscosity. For individual samples of yogurt were compiled flow and viscosity curve using Ostwald-de Waele model and based on Newton's law of viscosity, it was determined what kind of liquid was involved. Furthermore, it was observed whether the fat content and dry matter content had an effect on the density and viscosity of yogurt.
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Reologické vlastnosti různě tučných bílých jogurtů
Synková, Lucie
This diploma thesis Rheological properties of plain yoghurts with various fat content is aimed in its theoretical part on the basic summary of fermented milk products. It is focused mainly on yoghurts, especially plain yoghurts. The manufacture, composition, nutritional and health benefits, storage and shelf-life of yogurts is described. In the next chapter are described rheological properties of foods. The aim of the practical part is to assess rheological properties of plain yoghurt with various fat content. All samples are commonly available in the Czech shops. The range of fat content was 0,1–10,2 g/100 g. The dependency of shear stress on shear rate was studied as well as the dependency of apparent viscosity on shear rate (1,02–68 s-1). The rheological properties were fitted to Ostwald-de Waele model (the Power law). It was assessed that yoghurt is a Non-Newtonian fluid with shear thinning behaviour. Determination coefficients achieved high values (0,8748–0,9905). Time dependency and effect of various temperature (4 °C, 12 °C and 22 °C) on apparent viscosity was assessed. pH, titrable acidity, fat content and dry matter content were observed for all samples.
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Výroba jogurtů tradiční technologií
Pálová, Klára
The bachelor thesis deals with the production of yoghurts by a traditional technology. It describes the technological processes of the production, from the acquisition of basic raw materials, health-conscious milk to the realization of the final product, the yoghurt. The thesis deals with the composition and properties of the milk used in the production of yoghurt and the gathered microorganisms necessary for the production of the yoghurt, especially the yoghurt bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus, which results in the formation of yoghurt. The history of yoghurt and its legislative definition, the yoghurt types, possible yoghurt deficiencies and myths that disseminate from an ignorance of yoghurt, are also mentioned. Also this bachelor thesis deals with the production of the Greek yoghurt.
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