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Preservative systems for natural cosmetics
Koblasová, Dana ; Veselá, Mária (referee) ; Zemanová, Jana (advisor)
The aim of this bachelor thesis is to evaluate the antimicrobial activity of naturally derived preservatives against selected microorganisms. Theoretical part is focused on description of the most used natural, naturally derived and synthetic preservatives, on the safety of preservatives and finally, the issue of contamination of cosmetic products by microorganisms. In experimental part, antimicrobial activity of 4 naturally derived preservatives was evaluated against selected microorganisms, which were bacteria Micrococcus luteus, Kocuria rosea, Bacillus cereus, Bacillus subtilis, Serratia marcescens and one yeast Candida vini. The tested preservatives were from MinaSolve company - E-LEEN Green A, which contains pentylene glycol and phenylpropanol, E-LEEN Green OR, which is composed of citrus extracts, citric acid, ascorbic acid and pentylene glycol, Green B, which contains benzoic acid, sodium benzoate and pentylene glycol and Hexam+, which is a mixture of pentylene glycol and hexamidin diisethionate. Antimicrobial activity was evaluated by agar diffusion method. The highest antimicrobial activity showed Hexam+, the lowest E-LEEN Green OR. E-LEEN Green A and Green B did not show any antimicrobial activity against any microorganism in the 1% tested concentration. The measured values of the inhibition zones show that the most resistant microorganisms from all the tested in this thesis are Bacillus cereus and Bacillus subtilis and the least resistant are Micrococcus luteus and Kocuria rosea.
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Extraction of arabinoxylans from wheat bran
Koblasová, Dana ; Kouřilová, Xenie (referee) ; Diviš, Pavel (advisor)
This diploma thesis is focused on the use of wheat bran as a raw material for extraction of arabinoxylans. Wheat bran is a waste product of mill processing of wheat into flour and is mainly used as a livestock feed. However, the amount of bran produced significantly exceeds its consumption as feed, which opens up space for research into their further use. Polysaccharides such as cellulose, hemicelluloses and lignin are mainly present in the bran. The most common type of hemicelluloses are arabinoxylans, which form the main structural component of wheat bran. Alkaline extraction disrupts hydrogen and covalent bonds and releases polysaccharides of various molar weights from the crosslinked cell wall structure. Hydrolysis is required to obtain arabinose and xylose. Trifluoroacetic acid was chosen for the hydrolysis. The acid breaks down glycosidic bonds of the poly- and oligosaccharides to give the corresponding monosaccharides. The experiments made during this thesis have shown that the yield of multi stage extraction is twice as high as the yield of single stage extraction. Hydrolysis of the solid fractions after alkaline extraction revealed that a relatively large amount of arabinoxylans and other carbohydrates still remain bound in the complex matrix of the bran cell wall. Thus, alkaline extraction alone may not be the best option for obtaining arabinoxylans on a larger scale, or process optimization must be considered. Extraction with the addition of hydrogen peroxide appears to be effective for large-scale extraction processes.
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Extraction of arabinoxylans from wheat bran
Koblasová, Dana ; Kouřilová, Xenie (referee) ; Diviš, Pavel (advisor)
This diploma thesis is focused on the use of wheat bran as a raw material for extraction of arabinoxylans. Wheat bran is a waste product of mill processing of wheat into flour and is mainly used as a livestock feed. However, the amount of bran produced significantly exceeds its consumption as feed, which opens up space for research into their further use. Polysaccharides such as cellulose, hemicelluloses and lignin are mainly present in the bran. The most common type of hemicelluloses are arabinoxylans, which form the main structural component of wheat bran. Alkaline extraction disrupts hydrogen and covalent bonds and releases polysaccharides of various molar weights from the crosslinked cell wall structure. Hydrolysis is required to obtain arabinose and xylose. Trifluoroacetic acid was chosen for the hydrolysis. The acid breaks down glycosidic bonds of the poly- and oligosaccharides to give the corresponding monosaccharides. The experiments made during this thesis have shown that the yield of multi stage extraction is twice as high as the yield of single stage extraction. Hydrolysis of the solid fractions after alkaline extraction revealed that a relatively large amount of arabinoxylans and other carbohydrates still remain bound in the complex matrix of the bran cell wall. Thus, alkaline extraction alone may not be the best option for obtaining arabinoxylans on a larger scale, or process optimization must be considered. Extraction with the addition of hydrogen peroxide appears to be effective for large-scale extraction processes.
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Preservative systems for natural cosmetics
Koblasová, Dana ; Veselá, Mária (referee) ; Zemanová, Jana (advisor)
The aim of this bachelor thesis is to evaluate the antimicrobial activity of naturally derived preservatives against selected microorganisms. Theoretical part is focused on description of the most used natural, naturally derived and synthetic preservatives, on the safety of preservatives and finally, the issue of contamination of cosmetic products by microorganisms. In experimental part, antimicrobial activity of 4 naturally derived preservatives was evaluated against selected microorganisms, which were bacteria Micrococcus luteus, Kocuria rosea, Bacillus cereus, Bacillus subtilis, Serratia marcescens and one yeast Candida vini. The tested preservatives were from MinaSolve company - E-LEEN Green A, which contains pentylene glycol and phenylpropanol, E-LEEN Green OR, which is composed of citrus extracts, citric acid, ascorbic acid and pentylene glycol, Green B, which contains benzoic acid, sodium benzoate and pentylene glycol and Hexam+, which is a mixture of pentylene glycol and hexamidin diisethionate. Antimicrobial activity was evaluated by agar diffusion method. The highest antimicrobial activity showed Hexam+, the lowest E-LEEN Green OR. E-LEEN Green A and Green B did not show any antimicrobial activity against any microorganism in the 1% tested concentration. The measured values of the inhibition zones show that the most resistant microorganisms from all the tested in this thesis are Bacillus cereus and Bacillus subtilis and the least resistant are Micrococcus luteus and Kocuria rosea.
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