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Production and characterization of protein isolates from different kinds of bran
Vybíral, Lukáš ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the use of various types of bran as a by-product in the milling of cereals. Mills create a huge amount of this material per year. The most common way of processing bran is mostly incineration and to a lesser extent it is used as feed for livestock. Depending on the type of cereal, bran contains 10-20% of protein, which disappears from the food chain due to combustion. Within the framework of sustainability and valorisation of waste, which has recently been largely discussed, great emphasis is placed on waste minimization whether in the field of its production or further processing. Due to the relatively high protein content, bran appears to be a suitable starting material to produce protein supplements. Proteins can be extracted from bran based on their different solubility at different pH. In the alkaline method, the proteins are first dissolved in an alkaline pH and then precipitated in an acidic medium. Lyophilization is followed by characterization of the extract in terms of yield, protein content, moisture, amino acid profile and digestibility. The highest yield was obtained with the oat bran isolate (13,5 ± 0,6 g of isolate per 100 g of bran). In terms of protein content, the best protein isolate was also obtained from oat bran (95,2 ± 0,4% protein in the isolate). Another determination was the analysis of the amino acid profile, in which a high content of arginine was found in all analyzed protein isolates from bran. Determination of digestibility showed very good digestibility of all produced protein extracts from bran.
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Development and characterization of new dairy products with increased fiber and protein content
Smatana, Igor ; Punčochářová, Lenka (referee) ; Pořízka, Jaromír (advisor)
The bachelor thesis was focused on the production and characterization of new dairy products with increased protein and fiber content. Ground wheat bran was used as the fiber source and wheat bran protein extract was used as the protein source. From an ecological point of view, it would be ideal if 100% of the raw material was used and nothing was left as waste. We tried to approach this by using the waste (by-product) that arises during the production of flour as an additive to dairy products. The theoretical part focused on the characterization of fermented and unfermented dairy products and their production, the nutritional value of proteins and fiber and the composition and benefits for human health of wheat bran, protein isolation from wheat bran and common analytical methods to determine rheological properties, viable cell numbers. water binding and sensory acceptability. Two basic dairy products were created, one fermented and one unfermented, and subsequently fortified with a source of fiber (wheat bran) and a source of protein (protein concentrate from wheat bran). All products were subsequently characterized for characterization. Water binding, rheological and sensory properties were determined. The fermented dairy product was also subjected to cytometric analysis to determine the number of viable cells. The experimental part describes the methods we use to prepare and characterize new products. After evaluating the measured data, options for optimizing the acceptability of products by consumers were proposed. The results showed that the organoleptic properties were negatively affected by the addition of wheat bran and protein concentrate.
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Study of the chemical processes during kombucha technology
Chludilová, Markéta ; Obruča, Stanislav (referee) ; Pořízka, Jaromír (advisor)
The kombucha drink is referred to as leavened tea with added sponge called a scobie. In this way, a low-alcohol beverage is obtained, which gains considerable popularity, especially due to the alleged beneficial properties for human health. The microbial composition of this beverage is very rich, consisting of bacteria and yeasts living in a beneficial symbiosis [11]. The microbial composition of the drink and its beneficial effects on human health are very closely related. This work deals with the analysis of the chemical composition of the commodity beverage, especially with regard to the content of major components such as organic acids, carbohydrates and ethanol. These analytes are among the most common and most profoundly found substances in the carbohydrate beverage and are very closely related to the microbial composition of the scoby itself [3]. Combo beverage samples were supplied by RebornFood, one of which is the commercial production of this drink on the Czech market. At the same time, this company bases itself on purely natural fermentation of beverages, and therefore it is not particularly involved in the production process. The results of this diploma work point to the effect of the scoby used and the associated occurrence of analytes in the beverage, as well as the production process associated with the formation of analytes, which is described in several articles. It is expected that this work will provide information both on the production conditions and on the chemical properties of the beverage related to the condition of the scoby, which will be used further, both for RebornFood and the material used to solve the technical problems of this beverage production.
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Analysis of wine by modern analytical methods
Škařupa, Přemysl ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This work is dedicated to the analysis of wines using modern analytical methods. The theme is divided into two chapters. The first part deals with the chemical composition of wine from major components to the elements in trace amounts. The second part gives an overview of the most important modern analytical methods used for analysis of individual compounds in the wine and evaluated these methods in term of various parameters.
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Beer foam stabilization using biosurfactants
Jandrtová, Sabina ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on a research of the foam stability of the beer. We specifically observed the influence of ethanol and surface tension on the foam stability, and influence of ethanol and surface tension on the height of the foam. It was observed the influence of the hop acids in non-alcoholic beers. Furthermore, different biosurfactants were added into to the beer to observe better stability of the foam. The theoretical part of this work describes the foam from the physical aspect. There are described fourth key events involved in foam formation. Then it focuses on the beer foam – its structure, substances that influence its behavior and measurement of the foam stability. In this part there are described biosurfactants as well – their characteristics, qualities, distribution and applications. The experimental part is dedicated to the influence of ethanol, surface tension, the amount of iso- acids on foam stability in beer. There is observed the influence of biosurfactants of the foam stability and surface tension, which are added into to the beer. For the measurement of the foam stability was used the Rudin method. Liquid chromatography with DAD detector was used for the measurement the amount of the hop acids. The surface tension was determined by tensiometer. According to the results addition of ethanol changed the characteristics of the foam stability, but it’s not easy to find correlation between the increasing amount of ethanol and its stability. It was found out, that there is connection between the amount of ethanol and surface tension. On the other hand, there is not much connection between the surface tension and foam height. Within the framework of addition of biosurfactants was observed, that these foaming agents interacted the surface tension of the beer (lowering), however these agents accelerated the fall of the beer foam.
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Determination of sweeteners and preservatives in energy drinks by HPLC
Zídková, Anežka ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This master´s thesis is focused on simultaneous determination of sweeteners and preservatives in energy drinks by liquid chromatography coupled with DAD and ELSD detection. The method was optimized for determination of aspartame, acesulfame K, saccharin, sucralose, steviol glycosides, benzoic acid and sorbic acid. Analyses were carried out on the Poroshell 120 EC-C18 column (4.6 x 150 mm, 2.7 m, Agilent) using mixture of methanol, acetone and water with formic acid and trimethylamine as a gradient mobile phase at a flow rate 0,5 mL•min-1. Validation parameters were determined (limit of detection, limit of quantification, repeatability and recovery). The validated method was applied on real samples.
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Developement and optimization of the method for the extraction of ferulic acid from wheat bran
Hubačová, Klára ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
Bachelor thesis is considering usage of wheat bran for an extraction of ferulic acid. Wheat bran is a large-scale by-product of milling industry which is produced during milling of cereals (wheat) into flour. This low-cost product is usually used as a livestock feed. An initiative is raised for some other potential applications, because too large quantity produced every year can not be consumed just as a feed. There is a significant amount of phenolic acids from which ferulic acid is the most abundant one. It was found out after examination of structure of the wheat bran. This acid is connected with polysaccharides of a cell wall. The alkaline hydrolysis was used to disrupt a linkage between ferulic acid and polysaccharides. Then ethanol was added to precipitate the polysaccharides and the mixture was filtered. The filtrate contains ferulic acid which has great health benefits such as anti-inflammatory, antioxidant, anti-carcinogenic, antimicrobial effect etc. It plays an important role as an agent against UV radiation in the cosmetic products.
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The ecological grape and wine production
Kalábová, Jana ; Pořízka, Jaromír (referee) ; Omelková, Jiřina (advisor)
Bachelor´s thesis is focused on technological processes of production of wine and now very mature producing organic wines. It describes the principles of organic farming and organic way of growing grapes. It provides basic information about grape wine, which is an important raw material for wine production. It refers also to the modern protection of ecologically grown plants from fungal diseases and pests. The aim of experimental part was to examine the effects of aqueous extract of dried sage to the growth of microorganisms. Sage contains protective substances effective in preventing of pests. The results showed, that the extract from the stems showed inhibitory effect on some selected microorganisms, but the extract from the leaves did not show inhibition.
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Preparation and basic chemical and physical characterization of biochar from wheat bran
Zouharová, Kamila ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
At present, the extraction of biochar and its use is a much-discussed topic in the chemical and research fields. The use of biochar is very often declined in the areas of agriculture, waste management, environmental improvement and the fight against global warming. In addition to these sectors, the topic of biochar is also addressed in the production of bio-diesel and bio-oil. Due to the current use of secondary products during biotechnological processes, the presented theoretical and practical study focused on the issue of obtaining biochar from bran by pyrolysis at different temperatures. Part of the practical part was the extraction of biochar from bran and its subsequent analysis, which could be used to characterize biochar obtained from bran by pyrolysis physically and chemically. The characterization of bran biochar was solved by various analytical methods. These techniques yielded, for example, pH, conductivity, particle distribution, elemental composition of biochar, porosity and content of polycyclic aromatic hydrocarbons. Thanks to this study, the properties of biochar and its possible applications in everyday life were characterized in detail. Given the very promising use of biochar obtained from bran, it can be said that this will be a very desirable topic for the future.
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Fortification of bakery products with protein isolate from wheat bran
Bidmonová, Karolína ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
Proteins, as the major structural component of all cells and tissues, along with fats and carbohydrates, are a key macronutrient in human nutrition. An insufficient protein intake in the diet can lead to health problems and increasing protein malnutrition. Food fortification plays an important role in eliminating this protein deficiency. Wheat products, as a widely consumed food, seem to be a suitable commodity for protein fortification. Wheat bran was selected as a suitable source of protein due to its availability, protein content and relative simply method of a protein isolation. In the experimental part, the protein was extracted from wheat bran and used to prepare the mixtures. The mixture contained T530 flour and the 5%, 10% and 15% addition of the wheat bran protein isolate. From these mixtures, doughs were prepared and were subjected to chemical and rheological analysis. Finally, wheat baguettes with the addition of wheat bran protein isolate were made. The texture and taste properties of the baked products were verified by sensory analysis. The mixtures of flour and whey protein and a sample of unriched flour were also analysed to compare the results. Applied tests have shown that the addition of protein influences not only nutritional and chemical but also rheological properties. The addition of wheat bran protein isolate had a negative impact on the taste properties of the baguette Higher addition of BPI caused the increase of the bitterness of products. Taste optimization could be a topic for future study.
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