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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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Development of cereal products for special nutrition with addition of yeast and algae extracts
Požgayová, Viktória ; Fialová, Lenka (referee) ; Márová, Ivana (advisor)
This diploma thesis focuses on the development of gluten-free cereal products enriched with yeast and algae extracts. The theoretical part of this thesis was focused on gluten-free cereals used in the experimental part, on microbial biologically active substances and on the possibility of their use in the food industry. A chapter devoted to the evaluation of food safety and additives in food industry was also included in this part. The theoretical part concludes with the description of the methods used to analyses of selected biologically active substances in the samples. In the experimental part of this thesis, three samples of gluten-free flours were analysed, i.e. flour labelled as gluten-free, corn flour and rice flour. The content of total saccharides, proteins, gluten, lipids and bioactive substances such as phenolic substances, flavonoids, antioxidants and ß-glucans were analysed in the samples. In the most of the tested parameters corn flour achieved the best results. In order to prepare the microbial extracts, commercially obtained biomass of Spirulina and Chlorella and cultivated biomass of carotenogenic yeasts Rhodosporidium toruloides and Rhodotorula kratochvilovae were used. The extracts were prepared using solvents labelled as GRAS (water, 96 % ethanol, hexane and their combinations). Lipids, proteins and active substances such as pigments, phenolic substances, antioxidants, vitamins and ß-glucans were analysed in the prepared extracts and biomass. Spirulina and Chlorella extracts showed higher concentrations of bioactive substances while yeast extracts contained higher concentration of carotenoids, lipophilic provitamins and ß-glucans. The safety of prepared extracts used in food applications was verified by the MTT test of cytotoxicity. None of the tested extracts showed cytotoxic effects. In order to prepare enriched cereal products, the corn flour, biomass of Spirulina, aqueous extract of Spirulina, ethanolic extract of R. toruloides and the combination of Spirulina biomass and R. toruloides extract were chosen based on the obtained results. Two types of enriched cereal products were prepared and in enriched products the increase of antioxidant activity, phenolic compounds and protein content was detected.
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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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