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Anthocyan pigments in selected fruits
Peprná, Tereza ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
This diploma thesis is concerned with determination anthocyanins dyes in elderberry (Sambucus nigra L.). In theoretical part there is described general characterization of the plant, its chemical composition, short view of elderberry breeding and possibilities of usage in food and medical industry. Bigger attention is paid to anthocyanins dyes. There is described their characterization, occurrence, factors that have an impact on their stability. Biosynhesis of the pigments and metabolism, benefit effects and their usage in food chemistry are then shortly sumarized. Methods of determination of anthocyanins are discused too. Next chapter deals with high performance liquid chromatography. At the end of theoretical part, there is sumarized findings of anthocyan dyes analysis by expert scientists in various matrix. In experimental part, total of 16 species of elderberry were analyzed. These species are from research and breeding institute of pomology in Holovousy. The dyes were identification and quantification by high performace liquid chromatography coupled with a diode array detector. Detection wavelenght was 520 nm. Gradient of mobile phase was optimilized because of shortening analyses time and resolution improvement. Four dyes were identified by HPLC: cyanidin-3-sambubioside, cyanidin-3-glukoside, cyanidin-3,5-diglukoside a cyanidin-3-sambubioside-5-glukoside. Total amount of anthocyanins ranged from 33627167,0 to 5525284,0 mAU•min-1. The most anthocyanins dyes were determined in Mammut species (33627167,0 mAU•min-1), the lowest amount was measured in Aurea species (5525284,0 mAU•min-1). The most abundant anthocyanin in all species of eldeberry fruit except Haschebrg and Aurea species was cyanidin-3-sambubioside. The concentrations of cynidin-3-glucoside in all of the berries were quantified using regression equation of calibration curve. Mammut species had the most amount of this anthocyan (0,486 mg•ml-1) and the lowest amount had Aurea species (0,033 mg•ml-1).
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Development of method for determination of qualitative parameters of cocoa powder
Vránová, Petra ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
The theoretical part of the master’s thesis is focused on a brief botanical characterization of the cacao tree and its most famous varieties discussed. Furthermore, the chemical composition of cocoa beans is described with an emphasis on theobromine and caffeine. There is also mention of the cocoa beans the cocoa bean processing technology for cocoa liquor and cocoa powder, which are then used in food industry. Additionally there is a shorta short description of the legal requirements relating to cocoa. In this part are also two chapters are devoted to the description of instrumentation of high performance liquid chromatography (HPLC) and inductively coupled plasma optical emission spectrometry (ICP-OES). The experimental part deals with analyzes of cocoa powder, cocoa beans, cocoa liquor and waste cocoa beans sold as a "tea mixture". A total of 10 legislation-recommended parameters have been identified in the listed raw materials, such as caffeine, theobromine and sucrose, heavy metal and potassium, fat content etc. The highest content of theobromine was determined in cocoa powder 178.363 mgl-1, caffeine in cocoa beans 16.096 mgl-1. All samples analyzed contained a little amount of sucrose as expected, the highest concentration was found in the tea mixture samples in both the water: ethanol sample of 84.069 mgl-1, and the sample solution in water of 65.897 mgl-1.
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Testing of commercial products for separators of lipids
Vlčková, Bohumila ; Vítová, Eva (referee) ; Omelková, Jiřina (advisor)
Diploma thesis was aimed at testing of five commercial products for separators of lipids. Performed study should to shown that in produts are presented lipase-produducing microoganisms, event. that in products are also lipolytics enzymes as addition. The products was cultivated by solid-state and submerged fermentations and subsequently was tested their properties as is lipolytic activity, the amount of free fatty acids etc. Solid-state fermentation used Tributyrin Agar Base where Tributyrin was used as a substrate. Submerged fermentation used special prepared medium where was olive oil. Methods using in this study served for detection and qualification of lipase-produducing microoganisms in individual products. For detection of lipase-produducing bacterial spieces was used Spirit Blue Agar. In this case was used Tributyrin and Tween 80 as a substrate. Lipolytic activity was measured by spectrophotometry and degradation of lipids was measured titrimetry. Performed study demonstrated that all tested products have ability to degradation of lipids.
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Aroma profile of selected types of fruit juices
Baštová, Daniela ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis is focused on determination the aroma profile of selected species of fruit juices (apple, grape, carrot, orange, blackcurrant and elderberry juice). The theoretical part deals with the composition and properties of selected species of fruits and their juices, then deals with juice‘s technological process and selected methods for the determination of aroma active compounds. The experimental part describes the instrumental and sensory analysis. The six pure fruit juices and five mixed fruit juices were used for instrumental evaluation. The aroma active compounds were extracted by SPME and subsequently identified and quantified by gas chromatography. The sensory evaluation was performed by ranking test and evaluation using hedonic scale.
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Aroma profile of cheese analogues
Studýnková, Hana ; Cetkovská, Jitka (referee) ; Vítová, Eva (advisor)
The aim of this bachelor thesis was to generally characterize cheese analogues and to identify the content of flavor and aroma active ingredients in chosen samples of analogues. Cheeses were manufactured at the Tomas Bata University in Zlín. The introductory section explains what generally processed cheeses and cheese analogues are, including their production. The importance, use and properties of cheese analogues are also described. The microstructure and changes during storage are also mentioned. Particular importance is devoted to their physicochemical and organoleptic characteristics. In the experimental section aroma active compounds of 3 types of processed cheese analogues containing various vegetable fats were identified and quantified. Cheese flavoring compounds were isolated by SPME method (solid phase microextraction) and assessed by gas chromatography. 5 groups of various aromatic compounds in different amounts: alcohols, ketones, aldehydes, fatty acids and esters were found. Finally, the cheese analogues and fats used were compared.
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Influence of capsaicin derivatives on pungency of chili peppers
Paulišová, Sabina ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
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.
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The assessment of aroma compounds in processed cheese analogues
Hornáková, Miroslava ; Babák, Libor (referee) ; Vítová, Eva (advisor)
The aim of this work was to identify and quantify aroma compounds in samples of processed cheese analogues made at Tomas Bata University in Zlin. Analogues are processed cheese products in which lactic part is replaced by another component, either partially or completely. Market price is lower because of this replacement and that is why it is more attractive for the consumer. However, this substitution changes aroma, taste and texture, and also contributes to a reduction of the cholesterol content. Theoretical part is dealing with literature review of processed cheese analogues, focusing mainly on the composition, properties and production technology. In the experimental part 5 samples of cheese analogues made by using different types of fats (butter, apricot, grape, black currant and linseed oil) were analysed, simultaneously used oils were also analyzed. Aroma compounds were isolated by using SPME (solid phase microextraction) method and then determined by GC-FID. The most of aroma active compounds were identified in cheese analogue with patial substitute for grape seed oil instead of butter. The largest concentration of aroma compounds was identified in cheese analogue with patial substitute for linseed oil instead of butter. The black currant oil contained the most of aroma active compounds of all measured samples of oils. This oil also contained the largest concentration of aroma compounds.
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Aroma active compounds in fruit distillates
Kocinger, Oskar ; Veselá, Mária (referee) ; Vítová, Eva (advisor)
This work deals with the identification of substances responsible for the taste and aroma of fruit spirits. Solid phase microextraction method coupled with gas chromatography and mass spectrometry (SPME-GC-MS) was used for extracting and identifying volatile substances present in a total of six samples of fruit spirits, namely 3 samples for plum distillate and 3 samples for apricot distillate. The results of the individual analyzes were compared and the most frequently occurring substances were identified. These compounds are most likely responsible for the typical aroma of fruit spirits of this kind.
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Refinery and characterization of grape oil
Prchal, Miroslav ; Vítová, Eva (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with the topic concerning the extraction of wine oil from grape seeds, the refining of the extracted oil and the characterization of grape oil. Grape oil was extracted from the grape seeds obtained from the harvest in September 2019 by the winery Vavricek (Brezi u Mikulova, Czech Republic). The received grape pomace was the mixture of Green Veltliner and Blanc Saugvinon. The oil was extracted from the separated seeds by using liquid extraction in n-Hexane. The extraction yields of grape oil were compared with the literature, involving the different extraction methods as well as different oil plants. For the refining of the grape oil have been applied more steps aiming for the removal of the lipophilic pigments. Different adsorbents of pigments have been applied. The purification efficiency has been proved by the investigation with the thin layer and the high-performance chromatography. Moreover, the gas chromatography was used to characterize the composition of the oil. Finally, the composition profile of the oil obtained by the liquid extraction before and after purification has been compared with the commercial grape oil, which has been received by cold pressing. The results of the work show that the winery waste produced in South Moravia is a valuable raw material, which can be used for the production and different products, e.g., grape oil and pigments (chlorophyll).
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Sensory evaluation of cheeses
Pecinová, Ester ; Vránová, Dana (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory evaluation of cheeses. The thesis focuses on Edam cheese and the selection of methods for its sensory analysis. In the theoretical part natural cheeses are characterised, their chemical composition, physical and chemical properties as well as their sensory properties are described, further they are classified from several points of view and also individual steps of manufacturing process of Edam cheese are described. After that the literature search was made focused on sensory evaluation, within the methods were chosen for the experimental part, specifically measuring of overall preference and liking/disliking, appearance, colour, texture, aroma and flavour ratings using the hedonic scale and rating of chosen flavour descriptors by the profile method. In the experimental part the selected sensory methods were applied on 3 samples of Edam cheese, manufactured in 3 different modes of heat treatment of milk. Two sensory panels were involved in the evaluation: consumers and experts. Cheese from the first production (65 °C 30 min) was evaluated as the most acceptable; on the contrary cheese from the second production (80 °C 30 s) was evaluated as the least acceptable.
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