|
|
Identification of lactic acid bacteria in fermented dairy products using amplification methods
Tycová, Martina ; Rittich, Bohuslav (referee) ; Španová, Alena (advisor)
Polymerase chain reaction (PCR) is molecular diagnostic method which allows the identification of lactic acid bacteria used in food industry. In this work species-specific PCR primers (targeted on highly conserved 16S rDNA region) were used for identification of bacteria of species Streptoccocus thermophilus in 10 randomly commercially accessible fermented milk products and for identification of species Streptococcus thermophilus in 25 lyophilisates collected in Culture Collection of Dairy Microorganisms Laktoflora (CCDM, Tábor, Czech Republic). The PCR products (968 bp) were detected using electrophoresis in 1,2 % agarose gel. Bacterial DNA was isolated from crude cell lysates by magnetic carriers P(HEMA co GMA) containing carboxyl groups. DNA was reversibly bind on their surface in the presence of high concentrations of poly(ethylene glycol) (PEG 6000) and sodium chloride. Phenol extraction of DNA was used as control. Streptococcus thermophilus strains were identificated using PCR in all analysed samples.
|
|
|
Influence of aroma active compounds on flavour of fermented dairy products
Tvrdková, Denisa ; Pšenáková, Ivana (referee) ; Vítová, Eva (advisor)
The theme of this thesis is to determine the aroma active compounds in fermented dairy products. These substances significantly influence the palatability of these dairy products. Five kinds of dairy products were analyzed. Two types of creamy yogurts, and three types of yoghurt milks were produced at the dairy Ekomilk Ltd. in Frydek - Mistek and four types of acidified milk, five kinds of creamy yogurts, two kefir milks and two clabbered milks come from production of the company Kunin, Inc. Ostrava - Martinov. The SPME extraction method was used for the determination of aromatics, subsequent analysis was performed using gas chromatography. Compounds contained in fermented milk products were identified and quantified on the basis of the measured standards. Total 39 compounds, including 16 alcohols, 7 acids, 6 aldehydes, 6 ketones and 4 esters were identified. Fermented dairy products were twice subjected to sensory evaluation by the ranking test and scale test. The assessors were chosen from students, postgraduate students and staff of faculty of chemistry BUT. Consumers evaluated very positively yogurts, yogurt drinks and acidified milks, while kefir milks and clabbered milks did not suit in some aspects.
|
|
|
Fermented foods as a part of today's diet
Sochůrková, Veronika ; Pejšová, Hana (advisor) ; Chrpová, Diana (referee)
This bachelor thesis is devoted to fermented foods, which play an important role in human nutrition around the world. These include foods such as fermented milk products, fermented meat and fish products, fermented cereals, legumes, fermented beverages and kvass pastries. The theoretical part of the thesis focuses on the types and nutritional significance of individual groups of fermented foods. It also addresses the health aspects of the gut microbiome and the potential risks associated with the consumption of fermented foods. The aim of the work in the practical part was to determine the popularity and frequency of consumption of the most common fermented foods using a questionnaire survey. The results showed that the consumption of sour-milk products, especially yogurts, is very popular and most respondents include these foods in their diet several times a week. Fermented vegetables, especially sauerkraut, are also very popular. Most respondents are also interested in the topic of probiotics, and more than half of the respondents have tried homemade fermented foods. keywords: fermented foods, probiotics, fermented milk products, fermented vegetables, fermented legumes, fermented cereals, fermented beverages, kvass pastries
|
|
|
Mikroflóra kysaných mléčných výrobků
Horňák, Tomáš
Fermented dairy products are made from milk fermantation, using lactic acid bacteria. This fermentation is called lactic acid fermentation and its main result is the conversion of lactose into lactic acid. Simultaneously, according to the type of lactic acid fermentation, bacteria used, and fermentation conditions, various substances with sensory and nutritional significance are made. The most important fermented daily products include yoghurt and yoghurt milk, fermented cream, acidophilus milk and kefir and kefir milk. This thesis is mainly about mikroflora of this products, both the most important that are required for production, as well as variety of undesirable microorganisms and pathogens and their influence on the final product. The practical part focuses on the mikroflora of selected kefirs and compares results with the current legislation.
|
|
|
Metody měření viskozity kysaných mléčných výrobků
Šebela, Roman
This bachelor thesis deals with the measurement of viscosity of fermented dairy products. The first part of this thesis describes viscosity, viscosity measurement methods, individual viscometers and their distribution according to the measurement principle. Another part of the literary review deals with milk and fermented milk products. It describes milk composition, milk processing for production of dairy products, characteristics of fermented milk products, their production, rheological properties and possibilities of use. In the practical part are described individual samples – white yoghurt, sour cream, sour milk, acidophilic milk and kefir milk. The results of the measurement of the viscosity of fermented milk products, which were carried out on a rotational viscometer at 5-25 °C, are summarized here. The results include comparison of individual samples and decrease of temperature viscosity values.
|
|
|
Influence of aroma active compounds on flavour of fermented dairy products
Tvrdková, Denisa ; Pšenáková, Ivana (referee) ; Vítová, Eva (advisor)
The theme of this thesis is to determine the aroma active compounds in fermented dairy products. These substances significantly influence the palatability of these dairy products. Five kinds of dairy products were analyzed. Two types of creamy yogurts, and three types of yoghurt milks were produced at the dairy Ekomilk Ltd. in Frydek - Mistek and four types of acidified milk, five kinds of creamy yogurts, two kefir milks and two clabbered milks come from production of the company Kunin, Inc. Ostrava - Martinov. The SPME extraction method was used for the determination of aromatics, subsequent analysis was performed using gas chromatography. Compounds contained in fermented milk products were identified and quantified on the basis of the measured standards. Total 39 compounds, including 16 alcohols, 7 acids, 6 aldehydes, 6 ketones and 4 esters were identified. Fermented dairy products were twice subjected to sensory evaluation by the ranking test and scale test. The assessors were chosen from students, postgraduate students and staff of faculty of chemistry BUT. Consumers evaluated very positively yogurts, yogurt drinks and acidified milks, while kefir milks and clabbered milks did not suit in some aspects.
|
|
|
Identification of lactic acid bacteria in fermented dairy products using amplification methods
Tycová, Martina ; Rittich, Bohuslav (referee) ; Španová, Alena (advisor)
Polymerase chain reaction (PCR) is molecular diagnostic method which allows the identification of lactic acid bacteria used in food industry. In this work species-specific PCR primers (targeted on highly conserved 16S rDNA region) were used for identification of bacteria of species Streptoccocus thermophilus in 10 randomly commercially accessible fermented milk products and for identification of species Streptococcus thermophilus in 25 lyophilisates collected in Culture Collection of Dairy Microorganisms Laktoflora (CCDM, Tábor, Czech Republic). The PCR products (968 bp) were detected using electrophoresis in 1,2 % agarose gel. Bacterial DNA was isolated from crude cell lysates by magnetic carriers P(HEMA co GMA) containing carboxyl groups. DNA was reversibly bind on their surface in the presence of high concentrations of poly(ethylene glycol) (PEG 6000) and sodium chloride. Phenol extraction of DNA was used as control. Streptococcus thermophilus strains were identificated using PCR in all analysed samples.
|
|
|
Consumer preferences of selected milk products
ČÁSENSKÁ, Julie
The aim of this thesis was to evaluate the offer of fermented dairy products in the market network, and evaluate the favourite flavours of yogurts among university students. Market research of fermented dairy products was conducted in 3 hypermarkets, all the products in the offer were recorded. A simple anonymous questionnaire was created in order to obtain the necessary data about the popularity of each flavour among university students. The questionnarie was presented to a selected group of university students in the age of 20-35 years and it was completed by a total of 400 respondents. The results showed that the most popular yogurt is the one with pieces of fruit, the most popular flavour is strawberry. Banana flavour is the least favorite flavour among the consumers. The survey also showed that the most important criterion when choosing a yogurt is the producer and price.
|
|
| |
|
| |
guest ::
