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Sensometric discriminant testing - comparison of paired comparison test and ranking test
Švarcová, Karolína ; Antoch, Jaromír (advisor) ; Omelka, Marek (referee)
Sensometric tests are useful for deciding if there exists a perceivable sensory difference between two or more products. The tests can be divided into two main groups - first for determining the existence of a difference based on a known and specified sensory attribute, and second for determination when the variance in the sensory attribute is not known. In this thesis we deal with sensometric tests from the first group and describe the contrast in the statistical approach of a test method that evaluates two samples and a test method evaluating more samples at once. Particularly, within the paired comparison test the calculations are based on the binomial distribution, whereas for the ranking test, statistical methods working with the ranks of random samples are used. To illustrate the process of a sensometric test, we execute a paired comparison test, and we show how a good test method for a given problem is chosen.
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Změny vybraného sušeného ovoce během skladování a jejich vliv na senzorickou jakost
HUDSKÁ, Miluše
Thesis is focused on thy drying of apples and their changes during long-term storage. The theoretical part was written using the research, which brings findings about the drying of apples, their requirements during sale, selection of right raw material, interventions against enzymes and sensory analysis. The sensory analysis was a significant part of the practical part, because the practical part was based on it. Objective of the thesis was to compare three varieties of dried apples. By the scaling-point test there were not discovered by differences between varieties, but during each assessed descriptor there was discovered, that the quality is decreasing. The serial test was used as a second test of the sensory analysis, which determined the development of sensory quality and ordering of samples from the best to the worst. It was discovered, that all there varieties kept their specific characteristics for five months, i.e. eight months from the commencement of production. Longer storage was assessed as inconvenient.
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Vliv surovin a technologie na senzorickou jakost čokolády
ŠINÁKLOVÁ, Petra
The theoretical part of the diploma thesis titled "The Effect of Raw Materials and Technology on the Sensory Quality of Chocolate" describes the commodity and the related legislation, the raw materials used for the production of chocolate, the substitutes for some basic raw materials, and the production procedures. The theoretical part also describes the significance of chocolate for human nutrition and analyses the defects that may occur in chocolate. The objective of the practical part is to ascertain the opinions of a selected group of consumers on the selected sorts of chocolates. The results are divided into two parts. In the first part I carried out a collective evaluation (men and women together), and in the second part I evaluated the results separately for each gender (men separately from women) in order to find out any differences in the sensory evaluation of this commodity between the groups. The evaluators' preferences between three sorts of dark chocolates of the same brand with a different cocoa quantity were tested and evaluated by means of a ranking test. The preferences between two sorts of dark chocolates with orange flavour produced by two different producers were evaluated by means of a pair test. I also carried out and evaluated a questionnaire survey aimed at ascertaining the liking for various sorts of chocolates with different composition.
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Sensory evaluation of a selected type of a meat product produced by various producers.
VLČEK, Jiří
The diploma thesis describes the issue of sensory evaluation of food and food products, in particular the sensory evaluation of a selected type of a meat product produced by various producers. Due to its great popularity with Czech consumers, ?Vysočina? salami was selected for the sensory evaluation. Six producers were randomly selected to undergo the testing. The evaluation was conducted in the laboratories of the Faculty of Agriculture of the University of South Bohemia. The testing was performed by 58 evaluators being the students and employees of the Faculty of Agriculture of the University of South Bohemia. For the purposes of the sensory evaluation, the method of a rank test was used for which each evaluator obtained one sample of the salami of each producer and was to rank the samples based on their quality from the best to the worst. Based on the sum of ranks, the following rank was determined: Vysočina Hodice, MP Krásno, Maso Planá, Kostelecké uzeniny, KMOTR ? Masna Kroměříž and Masna Příbram. In order to ascertain the demonstrativeness of differences among the evaluated samples, the Friedman?s method was used. The resultant value has shown that there are demostrative differences among the evaluated samples at the probability level of 99 %.
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