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Characterisation of chosen types of dairy products
Musilová, Lenka ; Buňka, František (referee) ; Vítová, Eva (advisor)
The aim of this thesis was to design technology of production soft cheese with white mold on the surface in a pilot plant conditions using unpasteurized milk that comes from grazing cows. This way I wanted to be closer to the traditional cheese manufacturing technology, over which today dominates the industrial. Final cheeses were subjected to sensory analysis in order to determine their acceptability for ordinary consumers. Sensory evaluation was carried out by two committees: students and seniors. Between the two committiees were noticeable differences, however, both commissions at the conclusion assessed the cheese as „good”. This evaluation was mainly based on lower ratings of taste (flavor) of the samples, which were quite strong and unusual for Czech consumers.
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Characterisation of processed cheese analogues
Chlebcová, Lenka ; Buňka, František (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the topic of cheese analogues, their characterization and qualitative and quantitative analysis of processed cheese analogues for determination the taste and aroma active compounds. The overall character of processed cheese analogues is theoretically compiled in the introductory part. Their utilization, causes of the production, market introduction, technological production process and microstructure, including their comparison with classical processed cheese are given here. Various kinds of fats were used for production of analyzed cheese analogues, therefore commonly used ingredients for their production, their physical-chemical and sensory properties have been described. Specifically butterfat, milk fat, coconut fat, palm fat and mixed oil. Samples used for the practical part of the diploma thesis were made at Tomas Bata University in Zlín. In the experimental part the profile of aroma compounds in individual cheese analogues samples was assessed by SPME-GC analysis. In total 34 compounds were identified. The results were evaluated and compared, with emphasis put on the influence of storage, different fats, different maturity of Edam cheese on the content of aroma active compounds and on overall sensory quality of the analogues.
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Characterisation of processed cheese analogues
Studýnková, Hana ; Buňka, František (referee) ; Vítová, Eva (advisor)
The aim of this diploma thesis was to identify and quantify the content of taste and aroma active compounds and to evaluate flavour of cheese analogue samples with various vegetable fats (coconut, palm, butter and mixed oils and butter) and differently matured Edam cheese using selected sensory methods. The samples were produced at Tomas Bata University in Zlín. Aroma compounds were extracted using SPME and assessed using gas chromatography. In total 43 compounds were identified, 14 alcohols, 9 aldehydes, 7 ketones, 8 acids, 5 esters and 1 terpene. Simultaneously the analogues were sensorially evaluated using scale, profile and ranking tests. The influence of storage time, type of fat and Edam cheese used on content of aroma compounds and sensory quality of analogues were evaluated. The cheese analogues with butter were sensorially evaluated as the best, with mixed oil as the worst. From the point of view of aroma compounds content, the significant differences between samples were evident. Using more matured Edam cheese, the content of aroma compounds declined, however, these samples were sensorially evaluated as better. The content of aroma compounds decreased also with storage time, which is more obvious in less matured Edam cheese. So all above mentioned factors influence the content of aroma compounds and thus the flavour of cheese analogues.
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Assessment of chosen aromatic compounds in foods
Ascherová, Adriana ; Buňka, František (referee) ; Vítová, Eva (advisor)
This diploma thesis is focused on aromatic substances occurring in food. The theoretical part describes their characteristics, the use of fragrances of plant origin for flavoring of food and points to their possible negative effects on the human organism. Twenty six potentially allergenic fragrances are thus identified in European legislation and an overview of their physical properties, occurrence and use is also processed in this work.The aim of the experimental part was to develop and validate a method for assessment of fragrances using headspace solid phase microextraction combined with gas chromatography (HS-SPME-GC-FID). The following parameters have been validated : repeatability, linearity, limits of detection (LOD) and limits of quantification (LOQ). The HS-SPME-GC-FID method was finally applied to selected samples of foods commonly available on the market.
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Characterisation of processed cheese analoques
Svítilová, Lenka ; Horváthová, Viera (referee) ; Buňka, František (advisor)
The aim of this diploma work is to characterise processed cheeses and their analogues, to identify and quantify aroma active substances in the samples of cheese analogues, to evaluate their flavour using selected sensory methods and to compare the acquired results with the flavour of corresponding classic cheeses. The theoretical part is focused on general characteristic, classification, production technology of the processed cheeses and their analogues and on the list of aroma active substances occurring in cheeses. Furthermore, the summary of the methods suitable for sensory and analytic evaluation of cheese flavour and for the isolation of aroma active substances is given here. The samples of cheese analogues were made in Tomas Bata University in Zlín from coconut fat, butter, palm fat, milk fat and sunflower-seed oil. The classic processed cheeses were acquired commercially in the chain-store Billa. The aromatic substances were isolated and quantified using SPME-GC method, the fibre with the polar stationary phase CARTM/PDMS was used. Overall, 44 aroma substances were assessed: 9 aldehydes, 17 alcohols, 3 esters, 10 ketones and 5 acids. Classic processed cheeses contained the largest amount of aroma substances, Edam cheese, used for the production of cheese analogues, the smallest. Aroma compounds found in cheese analogues were then compared with raw materials used (Edam cheese and various fats), with the analogues produced last year and with classic processed cheeses. Finally, the results of the SPME-GC method and the sensory analysis were compared. It is possible to state that there are noticeable extensive differences between classic processed cheeses and cheese analogues, especially in taste.
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Influence of producing technology on flavour of Edam cheese
Urbanová, Andrea ; Buňka, František (referee) ; Vítová, Eva (advisor)
This work deals with the problem of flavour of Edam cheeses, i.e. natural hard cheese with low heat curd. The samples came from dairy MILTRA B s. r. o. Městečko Trnávka. A number of aroma active substances contribute to flavour of cheese. From the chemical point of view they are volatile compounds, including alcohols, aldehydes, ketones, fatty acids, esters, lactones, terpenes etc. Their content increases during ripening by influence of proteolytic and lipolytic changes and creates aroma, which is characteristic for type of cheese. The development of these components was monitored in chosen Edam cheese (30 % fat in dry matter) by headspace-SPME/GC method. The fiber CARTM/PDMS 85 µm was used for extraction of aroma compounds. The samples were taken from cheesemilk up to technologically ripe cheese. In total 30 aromatic compounds were identified, their content increased during ripening. The first increase was observed after pressing and then especially in second part of ripening. For comparison Edam cheese samples were also sensorially evaluated during ripening. The ordinal scale and profile tests were used for evaluation of organoleptic properties (appearance, texture, taste, aroma). The sensory quality was improved during ripening, but significant changes were not observed with regard to fine taste and smell of Edam cheese given by globally low content of aroma active compounds.
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Assessment of chosen aromatic compounds in foods
Škopová, Jitka ; Buňka, František (referee) ; Vítová, Eva (advisor)
The thesis deals with the issue of potentially allergenic aroma compounds in food. Aroma compounds suitable for food flavouring are mainly of plant origin. These aroma compounds and their mixtures have a lot of positive and negative effects on human organism. Although the aroma compounds are not among main groups of allergens, several studies indicate a potential risk of allergenic effects of some aroma compounds. The theoretic part of this thesis focuses on aroma compounds of plant origin and gives an overview of 26 the most important fragrance allergens according to the European cosmetic legislation. The aim of the experimental part was to verify the selectivity and appropriateness of the currently used methodology of headspace solid-phase microextraction and gas chromatography-flame ionization detection (HS-SPME-GC-FID) for determination of selected allergenic aromatic active compounds. Secondly, it is to use a proven method for a wide spectrum of real food products.
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Composition of fatty acids in processed cheese analoques
Sůkalová, Kateřina ; Vespalcová, Milena (referee) ; Buňka,, František (advisor)
This thesis deals with the determination of fatty acids of processed cheese analogues. The aim is to identify and quantify the fatty acids in selected samples of cheese analogues. The introduction is a brief overview of the composition and properties of cheese analogues, technology and application options. The following describes the appropriate method for the determination of fatty acids in cheese and cheese analogues. Of these methods the largest part is devoted to gas chromatography, which is most frequently used method for detection of volatile fatty acids. Individual cheese analogues used for the analysis, contained various types of added fats. Specifically, the milk fat, coconut oil, sunflower oil, palm oil and butter. Samples of these fats were extracted and then converted to methylesters by methanol esterification with catalysis by potassium hydroxide. The most important fatty acids were identified and quantified in samples of cheese analogues using gas chromatography and compared with fatty acids of fats used for the preparation of these analogues are used.
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The effect of a storage conditions on aroma compounds in processed cheese
Štouračová, Anna ; Buňka, František (referee) ; Vítová, Eva (advisor)
The aim of this diploma thesis was to monitor influence of storage conditions (temperature and time) on content of aroma substances in sterilized processed cheeses and also on their flavour. The part of cheeses was stored at 6°C, second part at room temperature 23 °C and third part at 40 °C. Processed cheeses were produced by Madeta, a. s., sterilized at 117 °C 20 min. The analysis was made at regular intervals, cheeses stored 16 and 23 months were analysed in this work. The aroma compounds were isolated by SPME and subsequently identified and quantified by gas chromatography. In total 37 aroma compounds were identified and quantified, 7 aldehydes, 7 ketones, 6 acids, 12 alcohols and 5 esters. Total content of aroma compounds increases with higher storage temperature. The time of storage has also influence on content of aroma compounds, we may say, that content is increasing, although sharp growth was registered only after 23 months, namely in the thermostat. Simultaneously sensory analysis of cheeses was made. Ranking test and evaluation using scale were used. Cheeses from a fridge were always evaluated as the best in all categories. Cheeses stored at room temperature were evaluated worse and cheeses from thermostat were the worst. So it is apparent, that high temperature supports undesirable chemical changes in cheeses and certainly is related to their flavour.
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Elaboration and introduction of the method for determination of some proteins
Hruzík, Ondřej ; Buňka, František (referee) ; RNDr.Karel Gebauer (advisor)
Core protein of aggrecan has a significant share on the correct function of articular cartilage. Its lack or structural failure could be the reason for the disfunction of the cartilage. The culture of chondrocytes taken from a pork articular cartilage was used for the study of aggrecan production. The monolayer culture method offers the model system which has enabled us to watch the aggrecan production into growth medium. The aggrecan synthesis was stimulated in the media with addition of L-methionin, L-serin and sodium selenite pentahydrate. Methionin and serin are antecedents of sulphur amino acid of cysteine, whose role is incredibly important for the correct function of core protein. Growth media and chondrocytes were analysed with the help of the automatic amino acids analyzer unit after acid or oxidative hydrolysis. The analyse established the amino acid representation. The main attention was paid to cysteine. The changing concentrations of this amino acid were showing if the antecedents in the addition are used for its production and, therefore, if it is possible to stimulate the production of core protein with these antecedents. The results are discussed in the conclusion of this thesis. The next step should be the detection of the concentration of synthesized aggrecan by the immunological method. Presently this method is very expensive. Therefore, the method of setting the core protein of aggrecan with the help of suitable amino acid was used for the first tests.
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