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Biotransformation of ferulic acid to sensory active compounds
Opial, Tomáš ; Pernicová, Iva (referee) ; Obruča, Stanislav (advisor)
The bachelor thesis deals with the biotransformation of ferulic acid to sensory active substances. The experiment was based on monitoring the biotransformation potential of selected microorganisms by high performance liquid chromatography (HPLC) method while the cultivation was performed in two parallel runs and samples with added ferulic acid were divided into 24-hour effect and 48-hour effect of ferulic acid on bacterial cultures. Thermophilic bacteria and halophilic bacterium Halomonas neptunia have been found to be the most suitable candidates for the biotransformation of ferulic acid to sensory active substances. In both samples of Schlegelella thermodepolymerans (DSM 15344 and DSM 15264) was formed 33 mg/l and 76 mg/l of vanillic acid and 81 mg/l and 71 mg/l of 4-vinylguaiacol after 24 hours of ferulic acid effect. In a sample with T. taiwanensis was formed 61 mg/l of vanillic acid and 32 mg/l of 4-vinylguaiacol after 48 hours of ferulic acid effect, and in a sample of R. xylanophilus was formed 56 mg/l of 4-vinylguaiacol. In the sample with H. neptunia after 24 hours of ferulic acid effect was formed 296 mg/l of vanillic acid, which was up to 59% of the conversion of the added ferulic acid and in a sample with H. organivorans after 24 hours of ferulic acid effect was formed 71 mg/l of vanillic acid. However, after 48 hours of ferulic acid effect, vanillic acid degraded. In addition to screening of biotransformation potential, the sequence of bacterial enzymes, involved in biotransformation, was also compared with protein sequences in the database using the BLAST search tool. The presence of genes encoding enzymes involved in biotransformation has been demonstrated for almost all used microorganisms except H. neptunia, for which no gene has been identified. The highest number of genes present in bacteria was with the enzymes feruloyl-CoA synthetase, enoyl-CoA hydratase/isomerase, acetoacetyl-CoA thiolase and vanillin dehydrogenase.
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Printed indicator of pH value designed for food packaging
Valíková, Michaela ; Kovalčík, Adriána (referee) ; Veselá, Mária (advisor)
The aim of this diploma thesis was to design an intelligent indicator of pH value for food packaging. Intelligent packaging is a new group of packaging that is able to provide costumers real-time information on the quality of packaged food through various indicators. In the theoretical part, a search was made on the topic of intelligent packaging with emphasis on freshness indicators. A smaller part was devoted to the issue of food spoilage. Emphasis was also placed on the description of the main components of the functional layer, and on the issue of chitosan crosslinking. In the experimental part, the crosslinking of chitosan with the addition of polyvinylalcohol using vanilin was studied. Prepared layers were monitored for their solubility and degree of crosslinking, which was determined using the ninhydrin method. To create a colorimetric pH indicator, an anthocyanin extract obtained by extraction from red cabbage was incorporated into the composition. A total of 3 anthocyanin extracts were prepared, for which the total anthocyanin concentration was determined by the difference method. The color of the prepared layers was evaluated spectrophotometrically under the action of various concentrations of the ammonia gas. The stability of the layers over time was also monitored. The last part of the experiment was the application of the prepared layers in a package with real meat.
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Biotransformation of phenolic compounds by bacterium Schlegelella thermodepolymerans
Opial, Tomáš ; Dvořák,, Pavel (referee) ; Obruča, Stanislav (advisor)
The diploma thesis deals with the optimization of the biotransformation of ferulic acid into sensory active substances and production of P3HB by bacterium Schlegelella thermodepolymerans. Cultivation experiments were performed in a medium with various concentrations of ferulic acid. Four bacterial strains were used for these experiments. Attention was paid to the model strain DSM 15344, in which a bioinformatic analysis of genes encoding enzymes, that catalyzed the biotransformation reactions of ferulic acid was also performed. Ferulic acid metabolites, specifically sensory active substances such as vanillyl alcohol, vanillic acid, vanillin and 4-vinylguaiacol, were measured by HPLC. S. thermodepolymerans DSM 15344 exhibited a very fast utilization of ferulic acid already within 8 hours of cultivation. The highest yields of ferulic acid metabolites were detected between 8 and 24 hours depending on the initial concentration of ferulic acid. The main metabolites of ferulic acid were vanillic acid and vanillyl alcohol. Vanillic acid reached the highest concentration in 16 hours in the presence of ferulic acid at initial concentration of 0.5 g/l. The highest yield of vanillyl alcohol occurred in 8 hours with ferulic acid at initial concentration of 0.75 g/l. In addition to biotransformation to ferulic acid, the amount of produced P3HB was also measured by GC-FID. Schlegelella thermodepolymerans DSM 15344 produced the highest amount of P3HB at 72 h at the lowest initial concentration of ferulic acid (0.25 g/l). Within the bioinformatic analysis, the presence of one fcs gene was confirmed using the available databases and the BLAST tool, but this was not enough to construct the complete metabolic pathway of ferulic acid by the bacterium S. thermodepolymerans DSM 15344.
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Printed indicator of pH value designed for food packaging
Valíková, Michaela ; Kovalčík, Adriána (referee) ; Veselá, Mária (advisor)
The aim of this diploma thesis was to design an intelligent indicator of pH value for food packaging. Intelligent packaging is a new group of packaging that is able to provide costumers real-time information on the quality of packaged food through various indicators. In the theoretical part, a search was made on the topic of intelligent packaging with emphasis on freshness indicators. A smaller part was devoted to the issue of food spoilage. Emphasis was also placed on the description of the main components of the functional layer, and on the issue of chitosan crosslinking. In the experimental part, the crosslinking of chitosan with the addition of polyvinylalcohol using vanilin was studied. Prepared layers were monitored for their solubility and degree of crosslinking, which was determined using the ninhydrin method. To create a colorimetric pH indicator, an anthocyanin extract obtained by extraction from red cabbage was incorporated into the composition. A total of 3 anthocyanin extracts were prepared, for which the total anthocyanin concentration was determined by the difference method. The color of the prepared layers was evaluated spectrophotometrically under the action of various concentrations of the ammonia gas. The stability of the layers over time was also monitored. The last part of the experiment was the application of the prepared layers in a package with real meat.
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Biotransformation of ferulic acid to sensory active compounds
Opial, Tomáš ; Pernicová, Iva (referee) ; Obruča, Stanislav (advisor)
The bachelor thesis deals with the biotransformation of ferulic acid to sensory active substances. The experiment was based on monitoring the biotransformation potential of selected microorganisms by high performance liquid chromatography (HPLC) method while the cultivation was performed in two parallel runs and samples with added ferulic acid were divided into 24-hour effect and 48-hour effect of ferulic acid on bacterial cultures. Thermophilic bacteria and halophilic bacterium Halomonas neptunia have been found to be the most suitable candidates for the biotransformation of ferulic acid to sensory active substances. In both samples of Schlegelella thermodepolymerans (DSM 15344 and DSM 15264) was formed 33 mg/l and 76 mg/l of vanillic acid and 81 mg/l and 71 mg/l of 4-vinylguaiacol after 24 hours of ferulic acid effect. In a sample with T. taiwanensis was formed 61 mg/l of vanillic acid and 32 mg/l of 4-vinylguaiacol after 48 hours of ferulic acid effect, and in a sample of R. xylanophilus was formed 56 mg/l of 4-vinylguaiacol. In the sample with H. neptunia after 24 hours of ferulic acid effect was formed 296 mg/l of vanillic acid, which was up to 59% of the conversion of the added ferulic acid and in a sample with H. organivorans after 24 hours of ferulic acid effect was formed 71 mg/l of vanillic acid. However, after 48 hours of ferulic acid effect, vanillic acid degraded. In addition to screening of biotransformation potential, the sequence of bacterial enzymes, involved in biotransformation, was also compared with protein sequences in the database using the BLAST search tool. The presence of genes encoding enzymes involved in biotransformation has been demonstrated for almost all used microorganisms except H. neptunia, for which no gene has been identified. The highest number of genes present in bacteria was with the enzymes feruloyl-CoA synthetase, enoyl-CoA hydratase/isomerase, acetoacetyl-CoA thiolase and vanillin dehydrogenase.
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