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Assessment of fatty acids in selected type of cheese
Chmelařová, Adéla ; Sůkalová, Kateřina (referee) ; Vítová, Eva (advisor)
This bachelor thesis is focused on identification and quantification of free and bound fatty acids in commercially available white mold cheeses: Hermelín, Kamadet and Olmín, using gass chromatography withflame ionization detection. Theoretical part of the thesis is dealing with the classification of cheeses with the main attention to white mold cheeses. In a following part cheese production technology is described, lipids and fatty acids are characterised including the possible methods for their assessment, mainly gass chromatography. Experimental part the contents of free and bound fatty acids in selected samples of white mould cheeses were compared. The method in accordance with ČSN EN ISO 1735:2005 was selected for lipid extraction. Fatty acids were identified as methylesters using acid esterification with methanolic solution of bortrifluorid as a catalyst. In total 21 free and bound fatty acids were detected in samples.
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Characterisation and maturation process of Edam type cheese
Dostálková, Andrea ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the assessment of aroma compounds and free/bound fatty acids in model samples of Edam type cheeses. Various combinations of microbial cultures, basic mesophilic and four selected strains of thermophilic Lactobacillus casei and Lactobacillus plantarum, were used for cheese production. The main aim was to judge the influence of microbial cultures on content of measured parameters, the changes during ripening were also followed. The HS-SPME-GC-MS method was used for identification and semiquantification of aroma compounds. The lipids from cheese were extracted based on ISO 1735:2004, fatty acids were identified and quantified using GC-FID method after conversion to methyl esters by acid esterification with boron trifluoride in methanol. In total 50 volatile compounds were identified in samples, 11 alcohols, 5 aldehydes, 7 ketones, 6 acids, 10 esters, 3 lactones, 2 sulphur compounds and 6 „others“; all of them are considered as aroma active. About 30–40 compounds were identified in single samples, alcohols, acids and ketones were the predominant. The number as well as the content of compounds identified decreased slightly during ripening. In total 17 free/bound fatty acids were identified in samples, their content also decreased during ripening. Myristic, palmitic, stearic and oleic acids were the predominant. The significant differences (p
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Application of herbal extract into suitable food product
Chmelařová, Adéla ; Saláková, Alena (referee) ; Vítová, Eva (advisor)
This master’s theses deals with a production and characterization of hard candies, a type of non-chocolate sweets. Methods of candies production were optimised with focus mainly on boiling temerature which significantly affects product consistency and stability. Production process optimisation was based on methods of sensoric analysis and Karl-Fishcher titration used to determine the water content in the product. Plant extracts Plectranthus amboinicus and Aronia melanocarpa which were applied to hard candies are rich source of bioactive compounds upon which prepared candies were characterised. Optimal conditions for candies production were – boiling temperature 155 °C, volume of citric acid 0,4 %, volume of Plectranthus extract 2 % and volume of Aronia extract 3 %. There were 42 volatile compounds identified in a sample containing 2 % of Plectranthus extract. Based on their content , the most significant compounds were carvacrol (8,44 %), carotol (1,47 %) and levomenthol (0,99 %). Total content of polyfenols was measured to be 7,10 ± 0,55 mgg-1 per 1 g of hard candy sample, antioxidant activity of a sample was 66,19 ± 1,80 gml-1. It was identified that 42 of volatile compounds were present inside the sample with 3 % of Aronia extract. The most significant being carotol (30,67 %), menthol (1,52 %) and thymol (1,39 %). The overall presence of polyphenols was measured to be 13,87 ± 1,12 mgg-1 per 1 g of the candy sample, the antioxidant activity of the sample was 115,00 ± 2,86 gml-1.
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Characterization and optimization of sensory quality of jelly sweets
Knotek, Vojtěch ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis focuses on monitoring and optimization of moisture of starch during jelly sweets processing. The theoretical part focuses on technology of manufacturing jelly sweets and description of raw materials needed for production. The methods for measurement of starch moisture are briefly described. The experimental part focuses on stabilization of moisture of starch during jelly sweet processing, specifically when pouring gelatinous mass into starch forms. The drying scale method was used to measure starch moisture. Recommended starch moisture is up to 8 %. During the two-month measurement, this value was always 0.5 % higher. On the basis of the results of this work, slight modification in the starch drying was made. This led to a reduction in starch moisture but not yet optimal.
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Comparison of microbial metabolic production from waste and powder whey
Elefantová, Petra ; Vítová, Eva (referee) ; Babák, Libor (advisor)
The master’s thesis discusses the comparison of microbial metabolic production from waste and powder whey. Whey is obtained as a by-product of cheese production. Lactose (preferably whey) using lactic acid bacteria (eg. Lactobacillus) under suitable temperature conditions is converted to lactic acid. Effect of temperature, effect of salts and effect of yeast extract on lactic acid production by L. casei were investigated. HPLC metod was determined lactid acid. In the practical part were used bacteria of the genus Lactobacillus. It was found that for dried and waste whey is the optimal temperature of 35 °C. At this temperature is the greatest gain of lactic acid. The highest concentration of lactic acid was obtained by using 20 g of yeast extract for dried whey and for waste whey were used 24 g of yeast extract. When monitoring the effect of salt concentration on the production of lactic acid, it was found that using only MnSO4·H2O gain most of lactic acid.
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The assessment of basic chemical parameters of natural cheese
Školová, Dominika ; Babák, Libor (referee) ; Vítová, Eva (advisor)
The aim of this work was to determine basic chemical parameters of natural cheese, namely Camembert type (white mold cheese) and Emmentaler type (cheese with high-heat curd). Model samples of cheese were produced in a pilot plant using unpasteurized milk in"organic" quality. Based on the literature search following parameters suitable for simple and fast characterization of cheese composition were selected: dry matter (drying to constant weight), fat in dry matter (calculated), total nitrogen (resp. determination of protein content) by the Kjeldahl method and fats, resp. total lipids (extraction with solvent). The results were finally compared with samples of the corresponding cheese type purchased on the market.
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Sensory quality of selected types of sweets
Michalíková, Veronika ; Němcová, Andrea (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the sensory evaluation of selected types of non-chocolate sweets. In the theoretical part the production technology of non-chocolate sweets is described, including raw materials needed. Furthermore, basics of sensory analysis with characteristics of sensory evaluation and selected sensory methods are mentioned. The experimental part deals with the sensory evaluation itself; the selected sensory methods were applied on samples of gummy sweets. Four colours/flavours (strawberry, orange, lemon, apple) from five producers were chosen for evaluation, together 20 samples. The aim was to assess the differences in sensory quality of samples of the same type from different producers. Untrained assessors, from Faculty of Chemistry BUT, were invited for sensory evaluations. Significant differences were found among the samples, glossy appearance and pleasant characteristic taste contributed to the positive evaluation, on the contrary the rigid texture, bland taste and odour and possible off-flavour contributed to the negative evaluation.
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The characterisation of selected type of „bio“ dairy product
Hanychová, Silvie ; Trachtová, Štěpánka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory evaluation of kefir. Specifically the differences in the sensory properties of kefir produced using the same method from various types of milk were observed. The theoretical part was focused on kefir, its characteristics, composition and production using kefir grains. The experimental part deals with the comparison of four kefir samples based on sensory evaluation. The evaluation was made by the students from Faculty of Chemistry BUT, the untrained assessors. Therefore the evaluation results may be closely reflecting the opinions of common consumers. The samples of kefir were subjected to sensory evaluation by the ranking test and the pleasantness of chosen properties (appearance, colour, texture, odour and taste) was evaluated using a seven-point scale, as well as the overal acceptability of samples. The results were statistically processed and graphically evaluated.
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Stability and properties of combined beverages and fruit concentrates
Klatová, Kamila ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
This diploma thesis deals with the stability and basic properties of combined beverages and fruit concentrates. The theoretical part describes the production and use of fruit concentrates. Furthermore, the work deals with anthocyanic pigments and phenolic substances. The principle and instrumentation of liquid chromatography and electron paramagnetic resonance were described. In the next subchapter, the methods of determination of total anthocyanins and phenolic substances were described. The experimental part of the thesis described the determination of soluble solids, viscosity and antioxidant activity. The total content of phenolic compounds were determined by the Folin-Ciocalteua method and the total anthocyanins were determined by the pH-differential method. In the samples were determined cyanidine-3-glucoside and cyanidin-3-galactoside by liquid chromatography.
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The assessment of chosen characteristics of cheese fats
Koval, Dominik ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
This bachelor’s thesis deals with assessment of selected fat characteristics of natural edam cheese. The theoretical part deals with general characteristics of natural cheese and structure of individual components. The main objective was to introduce and optimize methods in a laboratory to simple analysis of fat in cheese. Fat numbers were determined. To optimize were used samples, which were purchased at regular food store. With optimized methods were analyzed samples of cheese produced in cooperation with the Institute of Food Technology of Tomas Bata University in Zlin.
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