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Chemical and sensory analysis of fruit juice from selected cultivars of European elder
Ješková, Kristýna ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
The aim of this thesis is the chemical and sensory analysis of the juice from fruits of cultivated varieties of elderberry (Sambucus nigra L.). In the theoretical part botanical description of elderberry including its distribution and places of existence are given. There are also mentioned medical effects and collection of various parts of the elderberry as well as breeding certain species and methods evaluating sensory features of the juice samples prepared from the cultivated varieties of elderberry. In the experimental part some chemical parameters (yield, soluble dry matter content, relative density, pH, titratable acidity, formol number, reducing saccharides) in the juice of berries of eighteen cultivated varieties of elderberry were determined. In fifteen cultivated varieties was made sensory evaluation using profile test and scale. The aim of the evaluators in the evaluation using scale was to evaluate the taste, smell, sensory quality and preferences according to seven point cathegorical hedonic scale. In the profile test, five point scale was used to evaluate the intensity of chosen flavours: acidic, sweet, bitter and others. Overall impression of the sensory evaluation was rather not positive. In majority of the samples the taste and smell were evaluated as good or satisfactory and their general acceptability, too. The juice from the wild elderberry was estimated as worse than in other samples, its taste, smell and overall acceptability were unsatisfactory. In majority of the cultivated varieties were the taste and smell estimated as unsatisfactory as well as their general acceptability.
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Sensory quality of fruit juices
Hamalová, Veronika ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
This Bachelor‘s thesis deals with the evaluation of sensory quality of orange juice from different producers. All selected samples were made from concentrate. In total five samples bought in Tesco Stores CZ in Brno were evaluated The theoretical part focuses on the composition and properties of orange and orange juice, and their production technology. The selected methods for sensory evaluation of foods are mentioned. The definition of orange juice according to Czech Standard 56 8541 is also presented in this part. The appearance, color, taste, smell and consistency were evaluated using ordinal scales, taste development using graphic scale. The ranking test was also included. Written results were graphically evaluated and statistically treated.
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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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Sensory quality of chosen types of beer
Lišková, Michaela ; Divišová, Radka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory guality of chosen types of beer. The teoretical part was focused on the production of malt and beer and raw materials needed and also an introduction to sensory analysis was described. The experimental part was focused on evaluation itself. Nineteen untrained assesors were invited for sensory evaluation, who evaluated five selected beer kinds using the preprepared form. Unstructured graphic scale with a verbal description of anchor points was used to evaluate the appearance and color, taste and odour, fullness, bite, foaming, bitterness and any off-taste or off-odour of each sample. Five-point category ordinal scale was used for assessment of the overal acceptability of the samples. Results of the analysis were then evaluated graphically and statistically.
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Evaluation of the sensory quality of bread
Mahdalová, Martina ; Vránová, Dana (referee) ; Vítová, Eva (advisor)
This work deals with the evaluation of sensory quality of selected samples of bread. The samples of bread were bought in TESCO Stores a. s. ČR in Brno. Totally five samples were evaluated, two of them were rye-wheat and three of them were wheat-rye. All products were packaged and sliced. Purchased samples were subjected to sensory evaluation by the ranking test and scale tests. The assessors judged three main organoleptic properties of bread – taste, odour (aroma) and texture. The results were written down in the questionnaires and consequently graphically and statistically evaluated. The assessors which took part in sensory analysis were chosen from students of Faculty of chemistry BUT.
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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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Viscosity and acidity of selected type of natural yoghur
BÁRTOVÁ, Zuzana
The aim of the thesis was to evaluate the acidity and viscosity of natural yoghurt depending on the different addition of skimmed milk powder and using of the methods of sensory analysis to evaluate the perception of these properties by young consumers. Part of this work was to analyse acidity and viscozity in selected kinds of natural yoghurts purchased in the market network of the Czech Republic (CR). The literature search mentions basic characteristic of yoghurts and their classification, acidity and rheological properities of yoghurts including the factors, which affect them and sensory analysis. In the experimental part of the study the acidity value, total solids and viscosity measurements were detected by physico-chemical analyses of samples of natural yoghurts. At samples of yoghurts with different content of skimmed milk powder the sensory evaluation was also subjected and the graphs of sensory profile were compiled. The observed results showed, that from the samples of yoghurts made in the laboratory was the most satisfactory sample containing 10 % of skimmed milk powder. At samples purchased in the market network of CR were detected very low leveles of titratable acidity.
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Use of sweeteners in soft drinks and their effect on the sensory quality
ČIHÁKOVÁ, Tereza
The subject of this thesis was to evaluate the use of sweeteners in a selected group of soft drinks in terms of influencing sensory quality. Using selected methods of sensory analysis were five kinds of non-alcoholic drinks evaluated - four orange lemonades and one mandarin, which contained different composition of sweeteners. Three out of five samples were suitable for diabetics, because they only contained synthetic alternative sweeteners, one sample contained fructose-glucose syrup and the last sample contained sucrose. Individual samples were assessed by evaluators divided into three groups according to age. First group were evaluators at the age of 11-14, pupils from primary school Kosova Hora, second group - students of University of South Bohemia and the last group were evaluators above 40. The aim of this thesis was to lead to different results in different groups, depending on the attitudes and habits. There were big differences recorded among studied samples. It is interesting that neither group had failed to identify the best sample E, which is only sucrose. The top rated samples were sample A containing aspartame and acesulfame K, and the sample D with fructose-glucose syrup. The worst samples were clearly identified samples B and C, containing three and four kinds of synthetic sweeteners. Last but not least the paper includes a questionnaire for consumers, whose aim was to find out what influences the respondents while buying soft drinks and what is their attitude towards subsitute sweeteners.
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Comparison of selected qualitative indicators of heat-treated meat products from various distribution networks
TESAŘOVÁ, Ivana
Meat products belong into a popular group of foodstuffs intended for human consumption. Upon cancellation of state standards after 1992 it was possible to register an increase in distribution of products into shopping networks under the same name but with different ingredients. An analysis of the content of basic ingredients and of the sensory quality was carried out on selected samples of heat-treated meat products (20 products, 17 producers) bought in various types of shops. The contents of basic ingredients (water, fat, salt, proteins, collagen) were measured in a laboratory with the help of the NIRFLEX N 500 instrument, and no results of measurement at the level of conclusiveness (p < 0.05) were statistically evidenced. The best evaluation was granted by the assessors (6 persons) to the sample of the "Junior" group from producer "Fleischwaren Berger" from the Billa supermarket, while the worst evaluation belonged to the sample of the "Chicken Junior" group from producer "Schneider Masokombinát Plzeň" from the Albert supermarket.
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The influence of selected parameters on the quality of meat products
ROUŠAL, Jiří
This Mater´s Degree Thesis focuses on the sensory analysis of the chosen products of the non-perishable meat products in the dependence on the production technology. Its aim is to compare what kind of the products is prefered by the consuments using the sensory analysis and then statistic evaluation. The theoretical part summarizes the findings of the sensory analysis of the products, it also includes the conditions of the analysis and the statistic evaluation, sense perception in general and the production technology of meat products. In the practical part is described the method and the results of the hedonic test performed. In the thesis were used for evaluation the samples of the non-perishable meat products of the leading Czech producers of non-perishable meat products distributed and available in the shops in the Czech Republic.
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