National Repository of Grey Literature 181 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
The assessment of fatty acids in cheeses
Rajnochová, Veronika ; Omelková, Jiřina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of fatty acids in natural Edam cheese. The theoretical part briefly characterize the natural Edam cheese, main attention is paid to lipids, fatty acids and the possibility of their determination by gas chromatography. In the experimental part the content of fatty acids in the model samples of natural Edam cheese produced at Tomas Bata University in Zlín was determined. The method according to ISO 1735 was chosen for extraction of lipids from the samples , the method according to ISO 5509 using methanol solution of potassium hydroxide was chosen for the esterification of fatty acids ,. The resulting methyl esters were determined by gas chromatography with FID detection.
Controlled production of lipids and lipidic substances by selected yeasts and microalgae
Szotkowski, Martin ; Kráčmar, Stanislav (referee) ; Huelva, Ines Garbayo Nores, University (referee) ; Márová, Ivana (advisor)
Karotenoidy jsou přírodní pigmenty vyskytující se v mikroorganismech jako jsou řasy, kvasinky a sinice. Představují nejrozšířenější skupinu antioxidantů s významným biologickým účinkem. V současnosti vzrůstá zájem o karotenoidy vzhledem k jejich příznivým vlivům na lidské zdraví. Chlorofyly jsou zelená fotosyntetická barviva, která nacházejí uplatnění v potravinářství jako intenzivní zelená barviva. Koenzym Q je znám svým pozitivním vlivem pro správnou funkci řady orgánů v lidském těle. Ergosterol je nedílnou součástí membrán kvasinek a hub. Je to provitamin D2, který je důležitou součástí imunitního systému. Mikrobiální lipidy, nebo také ‚‚Single cell oils‘‘ jsou charakteristické vysokým obsahem zdraví prospěšných nenasycených mastných kyselin, které lze využít ve farmacii či kosmetice. Mikrobiální lipidy jsou dále studovány jako alternativa pro výrobu biopaliv. Dizertační práce byla zaměřena na studium a možnosti optimalizace produkce lipidů a lipidických látek vybranými kmeny karotenogenních kvasinek, mikrořas a sinic. V rámci práce byly testované kvasinky rodu Rhodotorula, Rhodosporidium, Cystofilobasidium a Sporidiobolus podrobené kultivacím na sérií médií s různými C/N poměry v rozsahu 13 až 100, obsahujících upravené odpadní substráty z potravinářského průmyslu. Vybrané kmeny byly poté kultivovány v bioreaktorech v médiu obsahujícím kombinaci odpadních substrátů. Kultivace mikrořas rodu Desmodesmus, Scenedesmus, Chlorella, Coccomyxa, Chlamydomonas, Botryococcus se zabývaly optimalizací jednotlivých komponent média a aplikací různých stresů s cílem navýšení produkce studovaných metabolitů. V rámci experimentů s extrémofilní mikrořasou Coccomyxa byly provedeny pilotní velkoobjemové kultivace v otevřených nádržích. V závěrečné části byl provedeny pilotní screeningové a velkoobjemové bioreaktorové experimenty zaměřené na možnosti kokultivace karotenogenních kvasinek a mikrořas. Testované kmeny kvasinek byly s rozdílnou úspěšností schopny utilizovat média obsahující hydrolyzované odpadní substráty. Nejlepším kmenem byl Sporidiobolus pararoseus, který na médiích dosahoval nejvyšších produkcí biomasy i sledovaných metabolitů. Z testovaných odpadních substrátů byla nejlepší kombinace odpadního fritovacího oleje a hydrolyzátu kávové sedliny. Úspěšná optimalizace složení hlavních komponent minerálního média vedla k zvýšené produkci studovaných metabolitů. Největší vliv měl optimální poměr P/N a aplikace oxidačního stresu. Nejlepších výsledků dosáhly mikrořasy rodu Desmodesmus a Scenedesmus. Velkoobjemové kultivace Coccomyxy onubensis potvrdily rezistenci kultury proti kontaminaci vnějšími vlivy a schopnost růstu za vysoké teploty a intenzity světelného záření. Kokultivační experimenty potvrdily schopnost symbiotického růstu kvasinek a mikrořas. Nejlepších výsledků dosahovaly všechny testované kvasinky s mikrořasami rodu Demsodesmus a Scenedesmus a v menší míře i rodu Coccomyxa.
Metabolic adaptation of selected microalgal strains on various nitrogen sources
Kodajek, Matěj ; Šimanský, Samuel (referee) ; Szotkowski, Martin (advisor)
Microalgae and cyanobacteria are photosynthetic organisms that, together with other microorganisms (yeast, bacteria), are used in industry, because they produce a wide range of interesting organic substances. This thesis deals with the metabolic adaptation of microalgae Scenedesmus obliquus, Scenedesmus acutus, Scenedesmus dimorphus, Chlamydomonas reinhardtii, Coccomyxa sp. and cyanobacteria Synechococcus nidulans, Arthrospira maxima, Limnospira maxima, Anabaena torulosa, which were cultivated on various nitrogen sources. These strains are descibed in the theoretical part including the metabolites and their applications in industry. The experimental part describes all chemicals, aids, devices and methods used for cutivation and analysis of microorganisms. The aim of the study was to compare and find out which nitrogen source in the BBM and SPIRULINA medium is the most suitable for a particular strain in terms of production of total biomass and composition of individual metabolites. Sodium nitrate, ammonium sulfate, glycine, urea and whey protein were used as nitrogen sources. The content and composition of lipids in the biomass was determined by gas chromatography. The content of ubiquinone, carotenoids and chlorophylls was determined by liquid chromatography.
Application of microbial oils in cosmetics
Reichertová, Klára ; Uhlířová, Renata (referee) ; Němcová, Andrea (advisor)
This bachelor thesis is focused on the application of microbial oil in a cosmetic product. Eight strains of yeasts of the genus Metschnikowia were examined, namely Metschnikowia pulcherrima 145, Metschnikowia pulcherrima 147, Metschnikowia pulcherrima 149, Metschnikowia andauensis 129, Metschnikowia andauensis 1241, Metschnikowia sinensis 1244, Metschnikowia zizyphicola 1247 and Metschnikowia shanxiensis 1250 for production of microbial oil. Substrates made of technical hemp (hemp flour, hydrolyzate and a mixture of leaves and flowers) were used for cultivation. The cultivation was performed at reduced temperature with the advantage of lipid production. The composition and ratio of fatty acids were determined by gas chromatography According to these resulst was choosen the best lipid producer and the most abundant substrate. This was the strain Metschnikowia zizyphicola 1247 and the substrate of hemp flour. At the end of the practical part was prepared a cream, into which the microbial oil was mixed. Finally, an evaluation of the oil with regard to its use in cosmetics and a comparison with vegetable oil with the same fatty acid profile are given.
Separation of lipids from cell tissues
Kotland, Vojtěch ; Lacina,, Lubor (referee) ; Svěrák, Tomáš (advisor)
This master’s thesis is focused on lipid separation from tissue cells. Thesis is divided into theoretical and experimental part. In the theoretical part is summarized current knowledge about lipids, their properties and methods used to separate them from tissue cells. Those methods were compared and one of them was chosen to be used in the experimental part. Theoretical part is ended with reviews aimed towards the research in this area of chemistry. Experimental part describes factors affecting chosen method of lipid separation from tissue cells. The measurements were chosen so that they could be easily reproduced. Values for each factor were experimentally determined to increase the amount of fat separated. All factors were compared and based on their summarization the optimization for whole method was produced.
Determination of basic nutritional parameters in edible insects
Korček, Jakub ; Štursa, Václav (referee) ; Diviš, Pavel (advisor)
In this bachelor thesis is dicussed nutritional value of chosen insect species. Analysed samples consisted of worms, crickets and locusts. Analysed parameters were: total nitrogen, crude protein, total lipids and content of chosen elements. Total lipids were, after homogenization, determined by Soxhlet method, using diethyl ether as a solvent. Prior to protein and element determination, samples did undergo Kjehldal digestion process, using sulfuric acid. Weiniger catalyst was only added to samples digested for protein measurement. Element content was determined by optical emission spectrometry with inductively coupled plasma (ICP-OES). Crude protein was determined by Kjeldahl method. The highest protein content was determined in crickets. (75 ± 5) %. Locusts contained the highest lipid content (33 ± 2) %. We also found out, that samples were rich in calcium, potassium, manganese and zinc, which are all important elements for the proper functioning of our body. The results of this thesis prove, that insects can present nutritionally important food.
Optimization of extraction of pigments from yeast and algae cells
Šimanský, Samuel ; Mikulíková, Renata (referee) ; Márová, Ivana (advisor)
The presented diploma thesis deals with the extraction and storage stability of lipophilic pigments produced by selected strains of yeasts and algae. In this thesis, there was studied the influence of the selected solvents on the efficiency of extraction, as well as the effect of ambient temperature on the stability of the pigments during storage. The work is divided into two main parts, theoretical and practical part. In the theoretical part knowledge about algae, yeasts and their cultivation parameters is summarized. Furthermore, some information regarding the selected lipid metabolites, their properties and possibilities of application in various branches of industry is mentioned. The practical part deals with the preparation of extracts and stability tests. Extracts were prepared from selected biomass samples in solvents suitable for applications in food industry or cosmetics (ethanol and hexane). Subsequently, the long-term stability tests lasting 4 months and short-term stability tests lasting a total of 28 days were performed on these extracts. The pigments were determined by HPLC and spectrophotometrically, the fatty acid content was determined by GC. For the extraction of pigments from biomass, in the most cases ethanol appears to be the optimal solvent. However, for lipid extraction from biomass, hexane appears to be the optimal solvent for a significant number of samples. In most samples, storage in the freezer showed the most favourable effect on pigment stability, but some samples showed comparable stability even when stored in the refrigerator.
Application of physical and chemical stress factors in different stages of growth to autotrophic microorganisms
Sniegoňová, Pavlína ; Byrtusová, Dana (referee) ; Szotkowski, Martin (advisor)
Nowadays, the demand for metabolites produced by microalgae and cyanobacteria is still growing, due to their positive effects on the human body and health. These metabolites include mainly carotenoid pigments, that have antioxidant properties, which very attractive to consumers. These substances are mainly used in food supplements; however they are also used in the pharmaceutical industry. These substances include, for example, -carotene, but also chlorophylls, which are significantly involved in the photosynthesis process. Other important metabolites are lipids, which are part of cellular structures and serve a number of other functions. The theoretical part focuses on the description of algae and cyanobacteria and their cultivation. Furthermore, the influence of stress factors on the production of biomass and metabolites. Metabolites are then characterized in terms of properties and biochemical pathways leading to their production. Subsequently, there are mentioned evaluation techniques used to characterize the cultivated biomass. In the result part, the production properties are compared depending on the selected stress factors.
Microbial production of lipid substances using waste substrates
Árendásová, Veronika ; Szotkowski, Martin (referee) ; Němcová, Andrea (advisor)
This bachelor’s thesis examines the issue of lipid production, done through selected Metschnikowia strains gained from waste starch substrates. Produced lipids are extensively used in biotechnological processes. Cultivation utilised waste starch substrates, left over from food production, as they constituted an available and economical material. The study also monitored the growth of individual Metschnikowia strains in laboratory and reduced temperatures, using an optimal medium. The yeast’s production properties were analysed by means of gas chromatography. All selected Metschnikowia strains were able to produce lipid from waste substrates. Lipid production increased when a mixture of glucose and waste substrates was used. The amount of lipids and the share of fatty acids strongly depended on the strain and cultivation conditions. In all examined strains, monounsaturated fatty acids were represented most strongly. The Metschnikowia pulcherima 149 adapted best to waste substrates.
Study of production properties of Metschnikowia yeasts
Chadimová, Markéta ; Szotkowski, Martin (referee) ; Němcová, Andrea (advisor)
Metschnikowia yeasts are able to produce under different conditions different amounts of lipids, which have remarkable uses in biotechnology and industry. This bachelor thesis is focused on the study of cultivation conditions under which yeasts produce the most lipids and also deals with which fatty acids these triacylglycerols are composed of. The influence of cultivation conditions on the amount of biomass is also monitored. Five yeast strains were examined, namely M. pulcherrima 145, M. pulcherrima 147, M. pulcherrima 149, M. andauensis 129 and M. chrysoperlae 1158. Cultivation media with different C/N ratios, containing glucose or cheap waste substrates (glycerol, coffee and waste fat) were used for cultivation. The cultivations were performed at several temperatures and then the amount of grown biomass was determined, and the composition and ratio of fatty acids were determined by gas chromatography. As yeast that produced the most biomass per time was determined the yeast M. chrysoperlae 1158, which after 336 hours of growth at 15 °C was able to produce 10,66 g/l of biomass on a medium with a ratio of C/N = 100. The highest amount of lipids was obtained with yeast M. andauensis 129 at 8 °C on medium with a ratio of C/N = 100 (21,57 % lipids in dry matter). If biomass production is also taken into account, the best results are obtained by the yeast M. chrysoperlae 1158 at a temperature of 11 ° C on a medium with a ratio of C/N = 100 with a biomass production of 10,15 g/l and 19,58 % lipids in dry matter. This yeast was therefore further cultivated on waste substrates.

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