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Influence of aroma compounds on sensory quality of sweets
Motúzová, Eliška ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
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.
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Production and characterization of non-chocolate sweets with the addition of plant extracts
Knapovská, Pavlína ; Nábělek, Jakub (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the production and characterization of plant extracts of green tea (Camellia sinensis) and sea buckthorn (Hippophae rhamnoides) and non-chocolate sweets – hard candies with the addition of plant extracts. These plants are characterized by a high content of bioactive substances, upon which the prepared extracts and candies were characterised. Determination of volatile substances by HSSPME-GC-MS, antioxidant activity by method with ABTS, determination of total phenols by Folin-Ciocalteu method and sensory analysis were performed. The produced sweets were then compared with similar commercial products. A total of 6 volatile substances were identified in the sample of hard candy with the addition of green tea extract, the antioxidant activity of the sample was determined to be 253,3 ± 0,9 µgml–1 and the total phenolic content was determined to be 0,49 ± 0,02 mgGAEg–1 per 1 g of candy. A total of 8 volatile substances were identified in the hard candy with the addition of sea buckthorn extract, the antioxidant activity of the sample was determined to be 206 ± 3 µgml–1, the total phenolic content was determined to be 0,51 ± 0,04 mgGAEg–1 per 1 g of candy. The obtained results show that the addition of extracts increases the nutritional value (higher antioxidant activity, higher content of phenolic compounds) of produced candy; from a sensory point of view, however, only samples with green tea were evaluated positively, the addition of sea buckthorn extract was not very attractive for consumers, they considered sweets with sea buckthorn to be too bitter.
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Sensory quality of chosen types of meat products
Javorská, Kateřina ; Sůkalová, Kateřina (referee) ; Vítová, Eva (advisor)
This Bachelor’s thesis deals with the evaluation of sensory quality of meat products. The 5 samples of pork ham of different quality and from different producers were selected for evaluation. The theoretical part focuses on the composition and properties of meat and meat products, and their production technology. The selected methods for sensory evaluation of quality are also mentioned. Ordinal and graphical scales were used for sensory evaluation of samples. The assessors evaluated these basic characteristics of the ham samples - color, appearance in the cut, preparation, consistency, smell, taste, saltiness and tenderness. The results were written down in the prepared questionnaires which were subsequently statistically and graphically evaluated. Sensory analysis was performed by group of students from the Faculty of Chemistry BUT.
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The effect of the quantity and type of nuts used in the production of pâté on the product sensory quality
Mejzlíková, Blanka ; Kovalčík, Adriána (referee) ; Mikulíková, Renata (advisor)
This bachelor thesis deals with the sensory evaluation of pâté with nuts. The 9 samples of pâtés which contained different quantity of nuts and different types of nuts were produced for sensory evaluation. In the theoretical part pâtés are characterised, their history, composition and manufacturing are described. The part of literature search is description and chemical composition of nuts which were used for production of pâtés. Another topic is a description of conditionals and methods of sensory analysis and sensory evaluation of meat products. The practical part comprises production of test samples, samples for sensory analysis, evaluating the heat treatment and sensory analysis. Percentage amount of lipids and composition of fatty acids were determined by gas chromatography. Processing of results of sensory and chemical analysis of samples of pâtés was determined that the best samples were pâtés with cashew nuts and pistachios.
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Alcohol-free beers with herbal extracts
Vyskočilová, Terezie ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
This bachelor thesis deals with alcohol-free beers and herbal extracts, which are the beers flavoured with. In the theoretical part the methods of non-alcoholic beer production and the representation of the active ingredients in herbs are described. A total of 7 herbal extracts were prepared and added into 3 non-alcoholic Czech beers. Each variant was examined in order to detect changes of the content of active substances before and after the addition of the herbal extract. The content of polyphenols, flavonoids, bitter substances and iso-bitter acids as well as antioxidant activity were analyzed spectrophotometrically. Using HPLC/UV-VIS analysis a content of catechins was assayed. The two selected flavours were encapsulated into liposome; the particles were tested of size and stability. Sensory analysis of all herbal extracts including the encapsulated ones was performed to determine the response of consumers and flavour preferences.
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Characterization of goat milk
Pospíchalová, Alžběta ; Burdějová, Lenka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory evaluation of goat milk. The differences in the sensory properties of goat and cow milk samples were followed. In the theoretical part goat milk is characterized, its composition, physical and chemical properties as well as its sensory properties are described. After that the methods of sensory evaluation are described. In the experimental part three samples were subjected to sensory evaluation, two samples of goat milk and one sample of cow milk, by the untrained assessors, which means common consumers. The observed properties, evaluated using a seven-point scale, were appearance, colour, texture, odour, flavour, off-flavour and the overall acceptability of samples. The results were graphically and statistically processed. The sample of cow milk was evaluated as the best; the acceptability of goat milk was negatively influenced by bitterish taste with the goat off-flavour.
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Effects of the addition of fortified wine in the production of pates on the sensory quality of the product
Kmeť, Jan ; Slavíková, Zuzana (referee) ; Mikulíková, Renata (advisor)
The aim of this thesis is to evaluate effect of addition of fortified wine on sensory quality of pâté. Thesis deals with preparation of fortified wine enriched pâté and their suitability for consumption. Main ingreditents, mainly meat and fortified wine are described in theoretical part. Furthermore, the technology of pâté production, methods and conditions of sensory analysis are also listed in this thesis. A total of nine types of pâté were prepared, eight of these pâtés contained different amouts of selected fortified wines. By evaluation of thermosterilation process, prepared pâtés were suitable for consumption. The sensory analysis showed us that addition of fortified wine mailny affects appearence, colour and flavour of product. Most preffered were pâtés without addition of fortified wine. Pâtés that contained Santa Cruz pink porto Rosé wine and Czech liqour wine Agni were well rated.
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Bioflavouring of beer using new Czech hop varieties
Ondruch, Petr ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on bioflavouring of beer using new czech hop varieties. Dry hopping is a phenomem, that contributes to the attractiveness and diversity of beer and is nowadays gaining in popularity. The aim of this work was to determine the effect of dry hopping on sensory profile and analytical parametrs of dry-hopped beers using czech hop varieties. Sensory evaluation and chemical analysis of these beers were taken. The chemical analysis included determination of the basic beer characteristics, total phenolic a flavonoid content, antioxidant activity and the concentration of selected organic acids and chemical elements. It was found out that dry-hopped beers compared to the reference beer presented higher bitterness, antioxidant activity and contained higher amount of flavonoids. Also an increase in pottasium, manganese, copper, calcium and malic acid levels was reported. The pH of beer samples was not affected by dry hopping. Sensory evaluation showed that dry hopping had a positive influence on the overall enjoyment of the beer, which was mainly determined by the higher aroma and more intense bitterness. By summaring all the data, it is obvious that dry hopping of beer using new czech hop varieties has a positive effect on the quality of the final beer and these hop varities are suitable for further use in the beer industry.
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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.
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