|
|
Study of fruit ripening and storage
Langová, Jiřina ; Zemanová, Jana (referee) ; Babák, Libor (advisor)
There are many changes in fruit quality during its ripening and storage. The following four apple varieties were studied: Champion, Glostr, Golden Delicious and Idaret. Amount of reducing sugars, total amount of sugars, quantities of acids, refractive solids and loss of starch were monitored. The changes of parameters, the differences between the varieties and differences in storage were compared. Parameters were monitored from mid-August 2008, when the apples ripened. After the harvest, apples were stored in a cool box at 2 - 3 ° C and at room temperature 20 - 23 ° C. Apples stored in the cool box were analyzed till the end of March 2009, and apples stored at room temperature until the beginning of January 2009. Total quantity of sugars in all varieties increases before harvest, while it decreases after picking the apples. The quantity of reducing sugars in apples rises gradually and after their picking it falls significantly in apples stored at 20 - 23 ° C. In apples stored in the cool box it continues rising until the end of November, and then it also decreases. Losses of starch are considerable and they are accelerated after the harvest. The quantity of acids also decreases throughout and amounts of refractive solids increases. For all varieties there are significant changes in storage at 20 - 23 ° C. Temperature, therefore, significantly affects processing of sugars and acids in fruit respiration.
|
|
|
Study of chemical composition of atmospheric aerosols
Gazdošová, Lucie ; Čáslavský, Josef (referee) ; RNDr. P. Mikuška, CSc. (advisor)
Atmospheric aerosols play an important role in various atmospheric issues (effect to the radiation budget of the atmosphere, visibility reduction, smog production, destruction of stratospheric ozone, …). Epidemiological studies proved a correlation between increased mortality and high concentration of ambient particulate matter. Over the past decade, a growing attention has been focused on the organic compounds that are constituents of aerosol particles. Although organic compounds comprise often up to 60% of the total aerosol mass, their composition, concentration and formation mechanisms are not well understood. Diploma thesis will deal with the study of chemical composition of organic compounds bound to atmospheric aerosols with focus on polyaromatic hydrocarbons and sugars. Atmospheric aerosols will be sampled on filters and filter extracts will be analysed for content of studied organic compounds by means of GC, GC-MS or LC, respectively. Development and optimalization of extraction methods (PSE, …) and detection of compounds of interest. Concentration of studied organic compounds in aerosol size fractions PM 10, PM 2.5 and PM 1 will be compared.
|
|
|
Stanovení vybraných obsahových látek ve vínech metodou kapalinové chromatografie
Hermanová, Veronika
This thesis deals with the analysis of wines using high-pressure liquid chromatography in order to analyze the content of alcohols, organic acids, and carbohydrates in wine. The most important groups and their representatives are presented in the literary review, as well as the theoretical basis of chromatographic methods, selected types of detectors, and used stationary and mobile phases. In the experimental part, analytical parameters of wines from the retail network, laboratory-prepared must and wines prepared by fermentation were measured using liquid chromatography methods with refractometric and UV detection. The results indicate the suitability of this combination of detectors for the selected wine analyses.
|
|
|
3D tisknuté sensory pro detekci cukru v nápojích
Zichová, Anežka
Sugars are one of the most common ingredients in food industry, due to their diverse usage as technological component as well as sweetening element. The issue of sugar utilization is not only topic of food industry but plays a key role in human nutrition at the same time. The intake of simple sugars from food, particularly from sweetened beverages, is a major concern from a nutritional standpoint. Carbohydrates can be detected in variety of ways. A literature review was conducted on the methods used in food science, which is based on the previous characterization of the most frequently used sugars in food industry like sucrose, maltose, glucose, fructose, inverted sugar, and glucose-fructose syrup. The chemical, technological and nutritional properties of carbohydrates were described. Considering this examination, 3D printed electrodes were designed for detection of sugar, namely glucose, in beverages. In consideration of the available literature, electrochemical enzymatic biosensors were designed, using glucose oxidase as the sensing element to detect glucose in beverages. The electrodes, carrying the enzyme, were printed from PLA and graphene based conductive filaments. The electrodes were activated in chemical and electrochemical way. To bind the enzyme, a technique based on cross-linking and immobilization was used. Chronoamperometry and cyclic voltammetry were used to test the biosensor. Afterwards the real sample of a fruit juice-based non-alcoholic beverage was examined. The results were interpreted in the context of the applicable legislation of the European Union and, likewise, the legislation of the Czech Republic, in regard to the required data on food labels.
|
|
| |
|
|
Tradiční způsoby technologického zpracování ovoce z extenzivních výsadeb jako součást kulturního dědictví
Malenová, Daniela
This work deals with the most frequently used technological methods of fruit processing originating from extensive orchards. It describes the suitability of the use of these methods for individual cultivated fruit species in non-productive fruit growing. It partially maps harvest processors from extensive plantings and the availability of products on the market. One experimental part is devoted to laboratory evaluation of the content of basic nutritional indicators (vitamin C, dry matter, refractometric dry matter and pH value) of selected 11 old and regional varieties and the results are compared with the recommended methods of processing in literature. It was found that the stated uses of fruit correspond to the average measured values of the examined fruits. The second part of the experiment is devoted to a selected variety ´Jadernička moravská´ from 6 different localities, where differences were found, probably due to climatic, edaphic and orographic factors.
|
|
|
Dynamic light scattering in the world of biomolecules
Križanová, Katarína ; Hofbauerová, Kateřina (advisor) ; Bednárová, Lucie (referee)
Title: Dynamic light scattering in the world of biomolecules Author: Katarína Križanová Department: Institute of Physics of Charles University Supervisor: RNDr. Kateřina Hofbauerová, Ph.D., Institute of Physics of Charles University Abstract: Dynamic light scattering (DLS) represents a non-destructive method which can determine the hydrodynamic radius of particles in a sample by laser scattering. Consequently, their real sizes can be calculated or, in the case of proteins, molecular masses can be estimated. DLS is nowadays widely used for the study of biomolecules and their reactions, as is documented in the thesis in a brief review. Our experimental work was focused on the measurement of proteins by DLS - lysozyme was used as a model protein. The laboratory protocol for sample preparation and DLS measurement was successfully optimized. In the framework of methodology optimization, the ability of correct detection of small particles was tested using sucrose. We came to the lowest limit of particle dimensions measurable by DLS using sucrose. We were able to observe the linear dependence of the measured hydrodynamic radius on sucrose concentration in the solution and we were also able to determine the hydrodynamic radius of sucrose correctly, in agreement with literature. We practically demonstrated the...
|
|
|
Jakost vína ovlivněná sířením
Kostihová, Lucie
The diploma thesis “Quality of wine affected by sulphurization” is focused on problems related to sulphur dioxide and its influence on technological and sensory quality of wine. The theoretical part of the thesis briefly describes the production of wine, describes various forms of sulphur dioxide in wine and its bonds with various components of wine. There are also outlined ways of the sulphurizing wine, dosing as well as how sulphur dioxide can be reduced by other technologies or by substituting it with other substances. The practical part of the thesis then verifies the effect of sulphur dioxide to the content of acids, reducing sugars and alcohol in wine. The effect of sulphur dioxide to the colour intensity of selected varieties of white and red wines is investigated. The wine is then also reviewed sensory to evaluate the effects of sulphur dioxide to the quality of the wine comprehensively. The results show sulphur dioxide affects the colour intensity. If the wine contains more sulphur dioxide, the colour of the wine is lighter. This difference is more evident in red wines. Sulphur dioxide has no influence to parameters such as reducing sugars, alcohol and acids. Wines with lower content of sulphur dioxide are more sensory acceptable.
|
|
|
Metody měření cukernatosti v potravinářství
Krišová, Hana
This bachelor thesis deals with methods by which it is possible to measure the sugar content in the food industry. It describes principles and procedures of selected methods and gauges suitable for these methods. Individual meters are explained on what physical principle they work on. In the next section, the described methods of measuring sugar content are applied to specific samples. Food processing operations have been selected where metering can be met. There is a procedure and description of measurement in practice. In conclusion, there are results from practical determination of sugar content of selected drinks.
|
|
|
Consumption of fruits and vegetables among pupils of younger and older school age in Milovice
Hodonská, Eva ; Váchová, Alena (advisor) ; Hanušová, Jaroslava (referee)
The aim of this bachelor thesis paper was to investigate the overall awareness of pupils from the 3rd - 5th grade from a selected primary school in Milovice. The secondary objectives monitored whether fruit and vegetables are a daily part of the target group's diet, at the same time whether the pupils actually eat fruit and vegetables received during recess and lunch breaks. Another research goal was to address the benefits of Fruit and Vegetables in schools project. The theoretical part is devoted to healthy nutrition. It describes the functions of the main nutrients, there is emphasis on accessory nutrients, especially on vitamins, fibers and antioxidants, which emphasizes the necessity of eating fruit and vegetables. Part of the theoretical part is also the issue of nutrition of children and the short discussion on the project Fruit and Vegetables in Schools. At the same time, a chapter on the digestive tract has been included, as it is here that digestion and absorption of substances from food occurs. Given the target group, the paper states the nutritional recommendations for citizens of the Czech Republic with a focus on school aged children. The aim of the practical part of this thesis was to map out the consumption of fruit and vegetables in the 3rd - 5th grade in accordance with the...
|
guest ::
