This master´s thesis is focused on determination of aroma active compounds in non-chocolate sweets and their influence on sensory quality/flavour. The theoretical part describes production of non-chocolate sweets, characterizes aroma active compounds including allergenic ones, method for their determination by solid-phase microextraction and gas chromatography with mass detection. For experimental part were used as model samples gummy candies purchrased in regular market. Four flavors were used, specifically yellow (lemon), green (apple), red (strawberry) and orange (orange). The HS-SPME-GC-MS method was used to identify volatile aroma active compounds. To evalutate the sensory quality were used scales, a profile test, and a time course evaluation. Owerall 120 volatille compounds were identified including 8 allergens.

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 is focused on the influence of the three most represented capsaicinoids – capsaicin, dihydrocapsaicin and nordihydrocapsaicin – on the sensory properties of five varieties of chili peppers. Aji Lemon Drop, Serrano, Jamaican Yellow, Habanero Chocolate and Bhut Jolokia were selected for this thesis. Determination of capsaicinoids content was performed using HPLC-DAD. The content of capsaicin in dried fruits ranged from 359 to 320 gg-1, the content of dihydrocapsaicin in the range of 130–7 767 gg-1 and the content of nordihydrocapsaicin in the range of 7–456 gg-1. The pungency of the samples was 8 928–601 338 SHU. The sensory evaluation of selected varieties of chili peppers was attended by 20 evaluators representing ordinary consumers. The subject of the evaluation was mainly the intensity of burning and sharpness, its pleasantness and identification of the place of manifestation of thermal sensations. Furthermore, the onset of burning and sharpness from the insertion of peppers into the mouth, the duration of thermal sensations, the intensity of sweetness and juiciness, the presence of other flavors and the texture of the fruit. Statistically significant differences were observed between the evaluation results. The low intensity of burning and sharpness of the Jamaican Yellow variety was assessed as neutral to rather pleasant, while the high intensity of thermal sensations of the Habanero Chocolate and Bhut Jolokia varieties was perceived as unpleasant. The Aji Lemon Drop and Serrano varieties were judged very similar from a sensory point of view. By combining the results of capsaicinoids content measurement and sensory analysis, significant correlation relationships were found between the evaluated parameters. With a higher content of capsaicinoids in peppers, their pungency (expressed in SHU) increased, at the same time a higher intensity of thermal sensations and their longer duration were found during consumption. On the contrary, with a high intensity of burning and sharpness, the pleasantness of these perceptions decreased. The onset of these feelings did not affect the observed properties. The higher the intensity of juiciness, the higher the sweetness of the fruit; however, these properties were not significant in terms of the content of combustibles or the intensity of thermal sensations. The effect of individual capsaicinoids on the site of thermal sensation has not been statistically proven.

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.

Diploma work comparing some bakery pemixes by chemical and organoleptic analysis.

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.

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.

This diploma thesis deals with preparation and characterization of alcohol-free beers with different flavours. Five flavoured and four pure, commercially available beers were tested. Three alcohol-free beers were then selected and used for preparation of flavoured beers. Ingredients used for production of flavour were honey, raspberry, ginger and cranberry. Analysis was focused mainly on substances of phenolic nature. Flavoured beers were also tested in sensory analysis. Ingredients used for flavouring of beers and production of both alcoholic and alcohol-free beers are described in theoretical part of the thesis. Analysis of polyphenols, flavonoids, technological characteristics and anthocyanins was performed using spectrophotometric method. Phenolic substances were identified and quantified by HPLC/PDA. Ascorbic acid was analysed by HPLC-NH2/UV. Results proved an increase of polyphenols, ascorbic acid and anthocyanins during flavouring of alcohol-free beers in dependence of used ingredients. Sensory analysis showed that as the best rated was the Staropramen beer with raspberry flavour. On the contrary, flavoured Bernard beers were poorly rated.