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Alcohol-free beers with herbal extracts
Vyskočilová, Terezie ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
This bachelor thesis deals with alcohol-free beers and herbal extracts, which are the beers flavoured with. In the theoretical part the methods of non-alcoholic beer production and the representation of the active ingredients in herbs are described. A total of 7 herbal extracts were prepared and added into 3 non-alcoholic Czech beers. Each variant was examined in order to detect changes of the content of active substances before and after the addition of the herbal extract. The content of polyphenols, flavonoids, bitter substances and iso-bitter acids as well as antioxidant activity were analyzed spectrophotometrically. Using HPLC/UV-VIS analysis a content of catechins was assayed. The two selected flavours were encapsulated into liposome; the particles were tested of size and stability. Sensory analysis of all herbal extracts including the encapsulated ones was performed to determine the response of consumers and flavour preferences.
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Encapsulation of selected natural extract for food application.
Vyskočilová, Terezie ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
This diploma thesis deals with encapsulation of natural extracts. In the theoretical part the methods of encapsulation, materials for particle preparation, as well as application of encapsulation techniques in food industry were described. In experimental part selected natural extracts of propolis, green barley and probiotics were characterized. There substances were encapsulated into alginate and chitosan. In the total of 25 types of prepared particles long-term stability in some model physiological conditions as well as in four different model foods was evaluated. Additionally, stability of selected particles in several real milk-based products was followed too. The stability of particles was determined spectroptohometrically. In natural extract a content of polyphenols, proteins, chlorophylls, as well as total antioxidant activity were analysed. To analysis of probiotics optical and fluorescence microscopy were used. In propolis and green barley antimicrobial activity was tested too. Moreover, in the sample of propolis also cytotoxic assay was applied. Agar-chitosan was chosen as the best shell material for propolis due to its optimal stability in model physiological conditions as well as model foods. Liposomes were evaluated as unstable and were not recommended for further application. As the suitable shell material for powdered green barley starch-alginate (rate 1:4) and agar-chitosan were proposed, while the second one showed better stability for released proteins. Agar-chitosan shell material was usable for fresh green barley too. For probiotics encapsulation alginate or alginate-starch were chosen because of their porosity and possibility of nutrients diffusion. In real foods the best results were reached with application of probiotic particles into milk. Coencapsulation of powdered barley and probiotics did not confirm inhibition of culture growth. Neither the antimicrobial effect of propolis and barley nor the cytotoxic effect of propolis were confirmed.
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Encapsulation of selected natural extract for food application.
Vyskočilová, Terezie ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
This diploma thesis deals with encapsulation of natural extracts. In the theoretical part the methods of encapsulation, materials for particle preparation, as well as application of encapsulation techniques in food industry were described. In experimental part selected natural extracts of propolis, green barley and probiotics were characterized. There substances were encapsulated into alginate and chitosan. In the total of 25 types of prepared particles long-term stability in some model physiological conditions as well as in four different model foods was evaluated. Additionally, stability of selected particles in several real milk-based products was followed too. The stability of particles was determined spectroptohometrically. In natural extract a content of polyphenols, proteins, chlorophylls, as well as total antioxidant activity were analysed. To analysis of probiotics optical and fluorescence microscopy were used. In propolis and green barley antimicrobial activity was tested too. Moreover, in the sample of propolis also cytotoxic assay was applied. Agar-chitosan was chosen as the best shell material for propolis due to its optimal stability in model physiological conditions as well as model foods. Liposomes were evaluated as unstable and were not recommended for further application. As the suitable shell material for powdered green barley starch-alginate (rate 1:4) and agar-chitosan were proposed, while the second one showed better stability for released proteins. Agar-chitosan shell material was usable for fresh green barley too. For probiotics encapsulation alginate or alginate-starch were chosen because of their porosity and possibility of nutrients diffusion. In real foods the best results were reached with application of probiotic particles into milk. Coencapsulation of powdered barley and probiotics did not confirm inhibition of culture growth. Neither the antimicrobial effect of propolis and barley nor the cytotoxic effect of propolis were confirmed.
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Alcohol-free beers with herbal extracts
Vyskočilová, Terezie ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
This bachelor thesis deals with alcohol-free beers and herbal extracts, which are the beers flavoured with. In the theoretical part the methods of non-alcoholic beer production and the representation of the active ingredients in herbs are described. A total of 7 herbal extracts were prepared and added into 3 non-alcoholic Czech beers. Each variant was examined in order to detect changes of the content of active substances before and after the addition of the herbal extract. The content of polyphenols, flavonoids, bitter substances and iso-bitter acids as well as antioxidant activity were analyzed spectrophotometrically. Using HPLC/UV-VIS analysis a content of catechins was assayed. The two selected flavours were encapsulated into liposome; the particles were tested of size and stability. Sensory analysis of all herbal extracts including the encapsulated ones was performed to determine the response of consumers and flavour preferences.
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