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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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Assessment of aroma active compounds in cultivars of apples
Mahdalová, Martina ; Trachtová, Štěpánka (referee) ; Vítová, Eva (advisor)
The aim of this master‘s thesis was to determine the aroma active compounds and monitor the sensory quality of apples. The theoretical part deals with the description, composition and properties of apples, information about the aroma compounds, their determination and possibilities for sensory evaluation of apples is also given. The gas chromatography method combined with the solid-phase microextraction, utilized for the specification of aroma compounds, is described. In the experimental part, the SPME-GC-FID method was applied on selected cultivars of apples specially cultivated against apple scab (Venturia inaequalis), i.e. 24 genotypes and Golden Delicious as the control variety. In total 60 various aroma compounds were identified, 22 alcohols, 12 aldehydes, 11 ketones, 10 esters and 5 organic acids. The number and concentration of compounds identified differed according to the cultivars. Sensory analysis was performed using category ordinal scales and the profile test.
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Assessment of aroma active compounds in selected type of cheese
Páral, Marek ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of aroma active compounds in white mold cheeses, i.e. soft, mold cheeses maturing from the surface. In the theoretical part, cheeses are generally characterized, their chemical composition, properties and process of production are described. After that It´s focused on aroma active compounds. The metabolism of their formation in cheese and their determination by means of solid phase microextraction and gas chromatography with mass detection are described. In the experimental part of the bachelor thesis, the SPME-GC-MS method was used for identification and semiquantitative determination of aroma active compounds in three samples of white mold cheeses made in the Czech Republic purchased in a market. Comparison of cheeses showed differences in the number and types of determined compounds as well as in total contents. A total of 66 volatile compounds were identified in samples; of those 1 aldehyde, 17 alcohols, 19 esters, 9 carboxylic acids, 15 ketones, 1 sulphur compound ¨ and 3 hydrocarbons.
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Assessment of aroma active compounds in selected type of cheese
Páral, Marek ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of aroma active compounds in white mold cheeses, i.e. soft, mold cheeses maturing from the surface. In the theoretical part, cheeses are generally characterized, their chemical composition, properties and process of production are described. After that It´s focused on aroma active compounds. The metabolism of their formation in cheese and their determination by means of solid phase microextraction and gas chromatography with mass detection are described. In the experimental part of the bachelor thesis, the SPME-GC-MS method was used for identification and semiquantitative determination of aroma active compounds in three samples of white mold cheeses made in the Czech Republic purchased in a market. Comparison of cheeses showed differences in the number and types of determined compounds as well as in total contents. A total of 66 volatile compounds were identified in samples; of those 1 aldehyde, 17 alcohols, 19 esters, 9 carboxylic acids, 15 ketones, 1 sulphur compound ¨ and 3 hydrocarbons.
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Comparison of efficiency of selected esterification methods
Jagoš, Slavomír ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
The present thesis aims to determine the optimal method of analysis of fatty acids. The theoretical part offers a concise introduction to lipids, fatty acids and their analysis using gas chromatography with flame-ionization detection. The goal of the experimental part of this thesis was to test and compare three different types of esterification methods: basic esterification with methanolic solution of potassium hydroxide, acidic esterification with methanolic solution of hydrochloric acid and acidic esterification with boron trifluoride. By evaluating these methods from various aspects, including their yield, availability and safety of the used chemicals, and simplicity and speed of application, the suggested optimal method is the acidic esterification with boron trifluoride.
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Assessment of aroma active compounds in cultivars of apples
Mahdalová, Martina ; Trachtová, Štěpánka (referee) ; Vítová, Eva (advisor)
The aim of this master‘s thesis was to determine the aroma active compounds and monitor the sensory quality of apples. The theoretical part deals with the description, composition and properties of apples, information about the aroma compounds, their determination and possibilities for sensory evaluation of apples is also given. The gas chromatography method combined with the solid-phase microextraction, utilized for the specification of aroma compounds, is described. In the experimental part, the SPME-GC-FID method was applied on selected cultivars of apples specially cultivated against apple scab (Venturia inaequalis), i.e. 24 genotypes and Golden Delicious as the control variety. In total 60 various aroma compounds were identified, 22 alcohols, 12 aldehydes, 11 ketones, 10 esters and 5 organic acids. The number and concentration of compounds identified differed according to the cultivars. Sensory analysis was performed using category ordinal scales and the profile test.
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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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