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Use of some microbial oils in foods and cosmetics
Požgayová, Viktória ; Szotkowski, Martin (referee) ; Márová, Ivana (advisor)
This bachelor thesis focuses on preparation of microbial oils from oleaginous yeasts and the subsequent characterization of their properties and biological effects on organisms. The thesis is divided into two main parts, theoretical and experimental part. The theoretical part provides an overview of information about microbial oils and the possibilities of their current or future applications in food and cosmetic industry. It also describes other lipophilic metabolites synthesized by carotenogenic yeasts and briefly characterizes the carotenogenic yeast strains as well as analytical methods used in the experimental part. Experimental part was focused on the process of optimization of the extraction of lipophilic active compounds from yeast biomass. The best option proved to be the combination of three solvents such as dimethyl sulfoxide, hexane, and ethanol. Using this approach, the extracts were prepared from Rhodotorula kratochvilovae, Rhodotorula mucilaginosa, Rhodosporidium toruloides, Cystofilobasidium macerans and Sporobolomyces pararoseus biomass. All of the prepared extracts were characterised based on the content of lipophilic metabolites by UV-VIS spectrophotometry and by analysis on HPLC/PDA and GC/FID. Furthermore, the antioxidant activity, SPF, antimicrobial effect, and short-term stability of these extracts were determined. The best temperature to preserve these extracts proved to be 7 °C. Three extracts with the highest SPF values were chosen and added to the prepared cosmetic emulsion which was characterized and the sensory analysis was carried out. The MTT cytotoxicity assay on human HaCaT keratinocytes was realized for the three extracts that were added to the prepared cosmetic product as well as for their combination.
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Production and characterization of non-chocolate sweets with the addition of plant extracts
Knapovská, Pavlína ; Nábělek, Jakub (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the production and characterization of plant extracts of green tea (Camellia sinensis) and sea buckthorn (Hippophae rhamnoides) and non-chocolate sweets – hard candies with the addition of plant extracts. These plants are characterized by a high content of bioactive substances, upon which the prepared extracts and candies were characterised. Determination of volatile substances by HSSPME-GC-MS, antioxidant activity by method with ABTS, determination of total phenols by Folin-Ciocalteu method and sensory analysis were performed. The produced sweets were then compared with similar commercial products. A total of 6 volatile substances were identified in the sample of hard candy with the addition of green tea extract, the antioxidant activity of the sample was determined to be 253,3 ± 0,9 µgml–1 and the total phenolic content was determined to be 0,49 ± 0,02 mgGAEg–1 per 1 g of candy. A total of 8 volatile substances were identified in the hard candy with the addition of sea buckthorn extract, the antioxidant activity of the sample was determined to be 206 ± 3 µgml–1, the total phenolic content was determined to be 0,51 ± 0,04 mgGAEg–1 per 1 g of candy. The obtained results show that the addition of extracts increases the nutritional value (higher antioxidant activity, higher content of phenolic compounds) of produced candy; from a sensory point of view, however, only samples with green tea were evaluated positively, the addition of sea buckthorn extract was not very attractive for consumers, they considered sweets with sea buckthorn to be too bitter.
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Study of biological effects of some plant materials
Drabíková, Nela ; Byrtusová, Dana (referee) ; Márová, Ivana (advisor)
The presented bachelor thesis deals with the preparation of aqueous, ethanolic and hexane extracts obtained from plant sources with increased content of oil, their characterization and cytotoxicity testing. In the theoretical part, a review focused on basic information about the used plants and their effects on the human body was elaborated. Furthermore, the active ingredients of the extracts, methods of their determination and the principle of the cytotoxicity test were described. In practical part the content of polyphenols and flavonoids was determined spectrophotometrically. Further, total antioxidant activity was measured. The fatty acids composition and the percentage of individual fatty acids were determined by gas chromatography. Next, MTT cytotoxicity assay was performed using human cell culture to confirm the safety of extracts for potential use in food, cosmetic and pharmaceutical industries.
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Changes of antioxidants in selected fruits during long-term freezing
Štindlová, Jitka ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
In this bachelor thesis some low molecular weight antioxidants contained in strawberries, raspberries, blueberries and cranberries are described. In the theoretical part also general characteristics of these fruits are introduced. Experimental part was focused on analysis of the changes of selected antioxidant content in the fruits. These changes were monitored during storage in two different conditions – in refrigerator and in freezer. In refrigerator whole fruits were stored for 8 days. The experiment in the freezer was performed for 2 months and the fruits were stored in four different processed forms – as a whole fruit, whole fruit impregnated by sucrose solution, as a pulp and pulp mixed with sucrose. Antioxidant content in fruits was analyzed by HPLC and spectrophotometry. The highest total content of antioxidants was found in strawberries, while the lowest values were found in raspberries. During storage some part of original antioxidant content stayed conserved, the highest content was preserved in blueberries processed as a whole fruits and impregnated whole fruits.
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PREPARATION AND APPLICATION OF SOME BIOPOLYMERS, NANOPARTICLES AND NANOFIBRES FOR COSMETICS AND FOOD
Bokrová, Jitka ; Pekař, Miloslav (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on preparation of nanoparticles and nanofibers with natural active ingredient and testing their biological effects. Modern types of application forms were prepared from biomaterials based on one or more natural polymers. Chitosan particles were prepared from cross-linked polymer using ultrasonication. A mixture of soy lecithin and cholesterol was used for preparation of liposomes. Poly-3-hydroxybutyrate was used for preparation of combined liposomes, too. All liposome particles were prepared by ultrasonication. Nanofibers were obtained from polyhydroxybutyrate using electrospinning. Mixtures of low-molecular antioxidants obtained by extraction from natural sources were used as active ingredients. Different types of teas, barks, herbs, spices, fruits and vegetables were selected as sources of natural antioxidants. Total phenolic and flavonoid content and total antioxidant activity of extracts were determined using spectrophotometrical methods. Obtained natural extracts were subsequently used for encapsulation. Prepared application forms were characterized in terms of their physicochemical properties. Particle size was monitored by dynamic light scattering. Colloidal stability of particles in suspension was determined using zeta potential. Spectrophotometry was used to evaluate the efficiency of encapsulation of active compounds into particles. The morphology of the new type of combined PHB liposomes was monitored by electron microscopy. Chromatography was used for quantification of individual components of particles. Morphology of nanofibers and incorporation of active agent into their structure were monitored using FTIR-ATR spectroscopy and electron microscopy. Afterwards, antimicrobial, cytotoxic and genotoxic effects of preparations were evaluated. It was found that the most suitable types of extracts for liposome preparation are aqueous and lipid extracts of natural antioxidants. Prepared particles showed excellent stability and good encapsulation efficiency. The study confirmed that incorporation of polydroxybutyrate into liposome structure does not reduce neither the colloidal stability of the particle, nor the efficiency of encapsulation process. Antimicrobial and antimycotic effect of preparations against model microorganisms Micrococcus lutues, Serratia marcescens and Candida glabrata was detected. It was found that process of encapsulation increases the inhibitory effect of natural extracts of antioxidants. The safety of preparations was assessed using two human cell cultures: epidermal keratinocytes and HaCaT cell line. Assays of cell viability and plasma membrane integrity were used to determine cytotoxicity of preparations. Low toxicity of liposome particles was confirmed by a series of cytotoxic tests. Obtained data showed that association of phospholipid with PHB polymer does not cause a significant increase in cytotoxicity in human skin cells. Genotoxicity testing on model procaryotic organism confirmed zero genotoxic potential of preparations. The new type of combined particles and polymeric fibers cant thus be used as a carrier for active ingredients, complex natural extracts, antimicrobial agents and many others.
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Obtaining and complex charaterization of Aronia spp. extracts
Seidlová, Kateřina ; Zemanová, Jana (referee) ; Veselá, Mária (advisor)
Aronia (Aronia melanocarpa) is a berry fruit with distinctive sensory characteristics and health-promoting properties. Polyphenols are the main bioactive compounds found in aronia including natural pigments – anthocyanins. Bioactive compounds are usually obtained from natural materials by extraction, in this work, two methods of extraction were compared – maceration and PHWE. Based on the total phenolic content, maceration was chosen as a more suitable method and then was optimized with statistical model – Design of Experiment. Optimal conditions were set to temperature of 30 °C, extraction agent 50 % ethanol, solid-solvent ratio 10 g per 50 ml and time of extraction for 30 minutes. Extract obtained under these conditions was characterised by total phenolic content – 1441 ± 90 mg/100 g DW, total anthocyanin content 943 ± 8 mg/100 g DW and antioxidation activity by ABTS 24,78 ± 0,09 molTE/g. In total of 25 volatile compounds were indentified in the optimal extract with content > 0,5 %. Major part created aldehydes and esters, with the main compounds being benzaldehyde (32,25 %) and methyl hexanoate (21,37 %).
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Use of algae extracts in cosmetics
Plášková, Anna ; Rapta, Marek (referee) ; Márová, Ivana (advisor)
This thesis is focused on a preparation of extracts from selected species of algal and cyanobacterial strains, their characterization, a cytotoxicity testing and a use in cosmetic products. The theoretical part contains the review of a taxonomic classification and parameters of algae and cyanobacteria and basic information about used organisms. There is a description of the most significant factors influencing the algae cultivation and production of biomass. Further, active substances of algae and cyanobacteria, which could be used in cosmetic products as UV protective substances, were described. An overview of extraction techniques, encapsulation of active substance into liposomes and particles characterization, antioxidant activity analysis, and cytotoxicity tests is given too. In experimental part, antioxidant activity of algal extracts and chlorophyll a and carotenoid content were determined spectrophotometrically. The long-term stability of extracts was monitored for three weeks. Liposomes were prepared by sonification and encapsulation activity was analysed. The Dynamic Light Scattering method (DLS) was used for analysis of polydispersity and size of liposomes. Colloid stability of particles was determined by zeta potential. Cytotoxicity tests were performed using MTT assay. The prepared extracts, particles and lyophilized biomass of algal and cyanobacterial strain were further used as active substances in the formulation of cosmetic products (type o/w). These creams were tested on human skin.
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Preparation and characterization of biomaterials with natural UV filtres
Pavelková, Renata ; Čarnecká, Martina (referee) ; Márová, Ivana (advisor)
This presented diploma thesis is focuses on preparation and characterization of biomaterials with natural UV filters. The theoretical part is aimed at effects of sunlight on the skin and how to avoid these effects by using cosmetic products. The materials and methods for extraction of lipid part of the selected vegetable and microorganism species and methods for preparation and characterization of nanoparticles and emulsions were characterized. The practical part deals with extraction of lipid part of selected vegetable and microorganism species. The liposome particles with encapsulated active compounds were prepared. The particle size, polydispersity index, colloidal stability, encapsulation efficiency, SPF, antioxidant capacity, phospholipid content and cytotoxic effect on human keratinocytes were observed. These particles were used for preparation of the resulting emulsions. Their protection level on UV light were set and stability were tested by using analytical centrifugation.
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Changes of the content of some active substances in aplle and pear fruits during storage
Matějková, Markéta ; Halienová, Andrea (referee) ; Márová, Ivana (advisor)
In presented bachelor thesis low molecular substances antioxidants found in plant food were described. Antioxidants from apples and pears were studied in detail, particularly their changes during storage in different conditions. Fruit species were described more closely in this study. The theoretical part is focused on ripening and storage of the fruits. The most common diseases of apples and pears are introduced too. In the practical part changes of some antioxidant levels in apples Idared (red-yellow) and Golden Delicious (green-yellow) were analyzed. Apples were stored for 2 months in three various storage conditions – at standard ambient temperature in the lab, in cellar and in refrigerator. In regular intervals samples were taken and levels of low molecular antioxidants (vitamin C, total phenolics, total flavonoids) and total antioxidant activity in apple fruits were analysed and compared. A surface microflora of the apples was analysed during the whole storage time. The most suitable storage conditions exhibited cellar (9 °C, 38,4 %). Phenolic changes in apples were substantially lower than flavonoid changes, while ascorbate content decreased dramatically with the storage time. Antioxidant activity was related mainly to ascorbate levels, influence of flavonoid changes was observed too. Antioxidant parameters were analyzed also in pear fruits, whose were stored only for very short time.
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Study of Formation and Elimination of Acrylamide in Food Matrix during Heat Treatment.
Marková, Lucie ; Jarošová, Alžběta (referee) ; Buňka, František (referee) ; Šimko, Peter (advisor)
Acrylamide (AA) is a probable human carcinogen and undesirable contaminant which is produced by the reaction of reducing sugars with asparagine in plant foods during their thermal treatment above 120 °C. AA is most often determined by GC-MS and LC-MS/MS in isolates from the matrix in a wide range of foods. According to our observations, AA intake from food is higher among young people (from 1.8 to 3.8 µg/kg bw/day), which is consistent with the estimations of JECFA FAO/WHO from the year 2006. Considering the health risk, it is recommended to reduce AA formation in food during its processing, in particular exploiting the available experience. The aim of this thesis was to extend the knowledge of the possibility of AA elimination in selected types of thermally processed foods. The study was focused on cereal foods that contribute significantly to AA exposure, especially bread and sweet biscuits. The whole AA content in the bread is in the crust, which represents 5-15% of the bread. Crust of home-made bread contains approximately 30-75 µg/kg, however the marketed bread contains 2 to 10 times more of AA. This is due to the composition of bread mix, preparation conditions and baking. For maintaining the quality of home-made bread during the dry mixture shelf-life, optimization of bread mixtures was designed by increasing of yeast content, which proved positive effect on the reduction of AA content at sufficiently high activity of the yeast. Monitoring of AA content in assortment of sweet bakery products showed higher levels of AA in diabetic biscuits containing fructose instead of sucrose. Three of them even exceeded the reference value (500 µg/kg) more than 1.5 times for commodity "cookies". Elimination of AA by applications of the enzyme asparaginase has been designed for minimal interference in technology of their production. The concentration of the enzyme and the appropriate method of its use in industrial environment have been tested previously in model systems. In optimized conditions of the enzyme application, AA content in diabetic biscuits was reduced by more than 40% without affecting the organoleptic properties of the final product. Effect of the antioxidants on AA formation was also part of the study. AA content in gingerbread was reduced efficiently by the use of fennel, anise, cloves, vanilla and white pepper (by about 9-21%). Conversely, coriander and cinnamon significantly increased its content (by 18-54%). Since correlations between the DPPH• radical quenching activity of the spice extracts and AA content was not observed, the final content of AA was probably influenced by the chemical composition of spices and reactivity of the individual components in the matrix. Investigated methods appear to be suitable ways of elimination AA in some foods; however their specific use must be optimized with regard to the composition of the food, processing and the technology used. Estimated impact of application of the above-mentioned methods to the overall elimination of AA exposure showed that its intake in high school students from the Czech and Slovak Republic can be reduced on average by 10%. This decrease is a success to reduce the possible risk of cancer disease by eating foods with a high AA content. It is also important piece of information for food producers for further development of relevant methods for AA elimination which would help to reduce the AA intake from foods even more.
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