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

This thesis deals with the assessment of aroma active compounds in non-chocolate confectionery and their influence on sensory quality. In the theoretical part the production technology of non-chocolate confectionery from raw materials to final product is described. Furthermore, aroma active substances, including those potentially allergenic, are characterized, and the method for their determination by solid phase microextraction and gas chromatography with mass spectrometry is briefly described. Sensory analysis and sensory evalutation methods are briefly desribed. Within expermental part of the work selected parametres of the HS-SPME-GC-MS method were optimized, aroma compounds in samples of hard candies were identified, and 24 potentially allergenic aroma substances were identified and quantified. Finally, a sensory analysis of these samples was performed. Differences in the number and type of volatile compounds were found between the samples. Overall 393 compounds were indetified including 19 allergens.

This diploma thesis focuses on identification of aroma active substances and sensory analysis in samples of non-chocolate sweets. For experimental part jelly candies were chosen as model samples. Specifically gummy bears with strawberry, lemon, apple and orange flavour were used. The theoretical part deals with the legislation and technology of manufacturing non-chocolate sweets, characterization of aroma compounds including those which could be allergenic. Furthermore this thesis describes a method of their determination using solid phase microextraction and gas chromatography with mass spectrometry. The end of the theoretical part is dedicated to methods of sensory analysis that were used. In the experimental part, the chosen method HS-SPME-GC-MS was used to identify volatile aroma active substances in selected samples of jelly sweets. The substances that are potentially allergenic were also quantified. For the evaluation of sensory quality scales, profile test and overall acceptability were used. The single samples differ in number and type of volatile compounds depending on producer and flavour. Altogether 119 compounds were identified including 12 allergenic.

This thesis deals with the production and characterization of cheese analogues, i.e. products where some of the dairy components are partially or completely replaced by a non-dairy component. Model samples – Eidam type cheese and analogue with the addition of pistachio oil, were produced by a conventional technological process at MENDELU in Brno. Free and bound fatty acids, volatile substances and sensory quality were selected and monitored as the main characterizing parameters of the sample quality. The aim was to characterize the differences between the samples caused by the addition of nut oil in the monitored parameters. The HS-SPME-GC-MS method was used for the identification and semi-quantification of volatiles. The extraction of fats from the samples was performed with a mixture of solvents (diethyl ether, petroleum ether), fatty acids were converted to methyl esters by acid esterification with methanolic solution of boron trifluoride as a catalyst and subsequently identified and quantified by GC-FID. Descriptive scales and comparisons with standard were used to sensory evaluate the appearance, color, texture, odor, taste, and overall acceptability of the samples. The structure was monitored by electron microscopy. The results show that the addition of pistachio oil affects the sensory properties, the maturation process (higher content of volatile substances), the nutritional value (increased content of unsaturated fatty acids) and the stability of the product.

This diploma thesis deals with the determination of aroma compounds in selected species of less known fruits (sea buckthorn, cornelian cherry, rowanberry, medlar, japanese quince and chokeberry). The theoretical part is focused on the description of these plants, their chemical composition, possibility of utilization and processing. Aroma compounds were identified and quantified in experimental parts. The aroma compounds were extracted by solid-phase microextraction and analysed by gas chromatography. A total of 45 compounds were identified. This compounds included 17 alcohols, 9 ketons, 8 aldehydes, 6 acids and 5 esters. Concurrently, the sensory evaluation of these fruits was carried out. The profile test and evaluation using graphical scales were used for evaluation of pleasantness and intensity of taste and odour.

The aim of this diploma thesis was to determine the aroma active compounds in different varieties of black elderberry (Sambucus nigra L.) and in elder juices that were mixed in different proportions with grape juice. The sensory analysis of these juices was subsequently performed with focusing on their tastiness. The theoretical part deals with the description of the black elderberry, its occurrence, composition and use at home and in industrial processing, as well as a description of aroma active compounds, which have been previously identified in elder by various authors. In the experimental part aroma active substances were identified and quantified in seven selected varieties of elder. Solid Phase Microextraction method was used for their isolation and subsequent analysis was performed by gas chromatography. 39 aroma active compounds were identified totally in fruits of the black elderberry, of which 15 alcohols, 11 aldehydes, 7 ketones, 5 esters and 1 acid. 45 aroma active compounds were identified totally in elderberry juices, of which 19 alcohols, 8 aldehydes, 5 ketones, 7 esters and 6 acids. The sensory analysis of elder juices was performed using ranking test and evaluation using the scales.

This diploma thesis is focused on determination the aroma profile of selected species of fruit juices (apple, grape, carrot, orange, blackcurrant and elderberry juice). The theoretical part deals with the composition and properties of selected species of fruits and their juices, then deals with juice‘s technological process and selected methods for the determination of aroma active compounds. The experimental part describes the instrumental and sensory analysis. The six pure fruit juices and five mixed fruit juices were used for instrumental evaluation. The aroma active compounds were extracted by SPME and subsequently identified and quantified by gas chromatography. The sensory evaluation was performed by ranking test and evaluation using hedonic scale.

This master thesis deals with the assessment of aroma active compounds in fruits of currant (Ribes spp.). The theoretical part was focused on basic characteristics and chemical composition of currants, as well as the basic principles of techniques used: solid phase micro extraction (SPME), gas chromatography (GC) and sensory analysis. The main aim of the experimental part was to determine aroma active compounds in currants using SPME-GC-FID method. The profile and scale tests were used for assessment of sensory quality and tastiness of fruits. In total 18 varieties, among them 6 white, 6 red and 6 black currants, were evaluated. Fifty aroma active compounds were identified including 21 alcohols, 10 aldehydes, 2 acids, 8 ketones and 9 esters. The results were statistically evaluated using principal component analysis (PCA) to investigate the influence of single compounds on sensory quality of fruits.

This diploma thesis is focused on the problematic of assessment of allergenic aroma compounds in various matrices. In the frame of European legislation 26 of potentially allergenic compounds are stated, whose content in cosmetic products is limited. In the case of foods there is not such restriction so far. In the experimental part, the allergenic aroma compounds in chosen samples of cosmetic and food samples were identified and quantified using Solid phase microextraction in conjunction with gas chromatography. Sensory evaluation of aroma or taste is also included.

This thesis deals with the determination of aroma active compounds in non-chocolate confectionery and their influence on the sensory properties of these sweets. The theoretical part is focused on the 26 potentially allergenic substances and their determination by SPME-GC-FID (a solid phase microextraction, gas chromatography with flame ionisation detector) and sensory analysis. In the experimental part SPME-GC-FID method was used to identify and quantify aroma active substances contained in the selected samples of confectioneries commonly available in food market and find out influence of presence and amounts of these substances on sensory profile of selected confectionery.