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Effect of addition of microbial or vegetable oil on the efficiency of cosmetic products
Kovářová, Karolína ; Hoová, Julie (referee) ; Němcová, Andrea (advisor)
This thesis focuses on the influence of the fatty acid profile and the concentration of active substances on the abilities to hydrate and to absorb into the skin of cosmetic emulsions. Coconut and macadamia oil, which are common cosmetic ingredients, were used as vegetable active ingredients. The last active ingredient used was the microbial oil, which was prepared as part of this work. Four strains of oleaginous yeast Metschnikowia were tested for the overproduction of microbial lipids in various culture media. Based on the results of gas chromatography, the yeast strain Metschnikowia pulcherrima (149) was selected. The chosen culture medium contained apple cider as a carbon source and had a 10 % sodium chloride content, inducing osmotic stress. Cosmetic emulsions with different concentrations of active ingredients were prepared. These emulsions were tested by sensory analysis. After application, the skin was analyzed with a skin camera that measured desquamation and sebum. The degree of desquamation is directly related to skin hydration and the level of sebum reflects the ability of the emulsion to be absorbed into the skin. It was found that if the user is not used to applying hydrating cosmetic emulsions regularly, but only solves the immediate problem of dry skin, it is advantageous to use an emulsion with an active ingredient content of 5.0 % or more. However, commercially available hydrating creams typically contain effective vegetable oils in lower concentrations. Furthermore, it was found that microbial oil could be a very interesting cosmetic ingredient.
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