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Analysis of selected biologically active substances in cereal products
Skutek, Miroslav ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
Presented diploma thesis was focused on study of biologically active compounds, especially some sugars in cereal products. In experimental part the total of 29 different cereal materials, food industry waste products and natural complex matrixes (microbial polysaccharide, honey, beer) were used. As a part of this work optimization of analytical methods suitable for analysis of simple sugars, oligo- and polysaccharides was done. In cereal samples reduced and neutral sugars were analyzed spectrophotometrically and individual sugars were detected by chromatography. For HPLC/RI analysis optimal mobile phase composition and chromatography conditions were proposed. For mono- a oligosaccharides C18-NH2 sorbent, mixture acetonitril:water 75:25 as mobile phase and flow 1 ml/min were verified as suitable separation parameters. Thin layer chromatography of mono- and oligosaccharides was optimized too. Introduced chromatography and spectrophotometry methods were then applied to analysis of cereal samples. As a model sugar natural microbial polysaccharide pullulan was used to analytical method testing. In cereal products and food matrixes total neutral and reduced sugars as well as products of their acid and enzyme hydrolysis were measured. Detailed analysis of some glycoside composition was tested too. As the most usable method for both qualitative and quantitative analysis of cereal sugars HPLC/RI method was found. To detailed identification of malto-oligosacharides tandem LC/MS/MS technique using derivatization by 1-phenyl-3-methyl-5-pyrazolon was tested too.
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Cereals - Active Substances, Biological Effects and Selected Applications in Food Industry
Lichnová, Andrea ; Tremlová, Bohuslava (referee) ; Vávrová, Milada (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on the study of the biological effects of active compounds found in cereals, on the development of methods of analysis these effects, on the determination of the content of active substances and characterization of the relationship between composition and biological effects of cereals and cereal products. For the analysis several kinds of raw cereal samples (flakes, flour, germ, bran), flavored extruded cereal products and also samples of paddy and husked rice were chosen. To major types of analysed active compounds belong mainly phenolic compounds in the form of glycosides and aglycones, and also saccharides. Group parameters such as total polyphenols, flavonoids and total and reducing saccharides were determined spectrophotometrically, individual phenolics and saccharides were determined by high performance liquid chromatography (HPLC). TEAC, DPPH and CLAMS methods were used to determine the antioxidant activity. Indirect methods of determination of substances with antioxidant effect were used as well. Results of the total antioxidant activity were compared with values of antimutagenic/genotoxic activity obtained by several microbial test systems. Antimutagenic effect was expressed as a percentage of inhibition of effect of standard mutagen and could be considered as a potential preventive effect of cereals to DNA arising primarily by free radicals effect. The highest values of group and individual phenolics, antioxidant and antimutagenic activity were found in germs, bran, in buckwheat products and in coloured and raw rice. In flavoured cereal products addition of chocolate or fruit positively influences content of active phenolic substances as well as sugars, antixidant and antimutagenic activity. In a representative sample of Czech population, questionnairy study was performed to monitor interest in cereals and consumer preferences. The most of consumers consider cereals with chocolate flavour as less healthy than confirmed results of laboratory analyses. In this study some new food products were developed. Several types of model cereal products containing plant (fruit, vegetables) extracts were proposed. Extracts were added to cereals in freeze-dried and encapsulated form. The highest positive effect exhibited addition of local forrest fruit extract. Within preparation of encapsulated extracts several methods of preparing lipid or saccharides particles were also tested. The encapsulation efficiency of the methods and stability and size of particles were analysed. Optimal type of fortified cereal foods could be suggested based on the acquired results. Selected cereals were used as alternative carbon substrates (processed or raw) for the cultivation of microorganisms to produce enriched biomass usable in the feed industry. We can conclude that cereals in raw as well as processed form belong to universal foods and rich sources of biologically active substances. They can be processed by many ways. They can be used for direct consumption, as a part of new products and also undirectly as a substrate for feedstock.
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Monitoring of cereal products uptake in a sample of Czech population
Vlachová, Martina ; Hurtová, Jana (referee) ; Márová, Ivana (advisor)
This bachelor’s thesis was focused on monitoring of consumption of cereal products and analysis of some of their active components. In theoretical part an overwiev of cereals and their composition was introduced. In experimental part a set of analytical parameters was obtained in selected cereal products: total phenolics, total flavonoids and antioxidant activity. The highest level of these active substances was detected in products containing chocolate and forest fruit. Further, 161 completed consumer questionnaires were collected. From these data common knowledge in consumers, their shopping conventions and individual products preferences were evaluated.
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Analysis of active phenolics in some cereal products
Vondráčková, Hedvika ; Vávrová, Milada (referee) ; Márová, Ivana (advisor)
Presented diploma thesis was focused on study of phenolic substances in various cereal products. Flours, brans and germs from various cereals, flakes and extruded cereals were chosen as samples. Phenolic substances were analyzed by spectrophotometry, RP-HPLC/UV-VIS and RP-HPLC/PDA/ESI-MS. Studies of saccharide content which were analyzed by spectrophotometry and HPLC/RI was incorporated to this thesis. Differences in the content of phenolic substances released from glycosides after acid hydrolysis of samples and differences in saccharide content determined after acid and enzymatic hydrolysis of samples were investigated. Simple sensory analysis of extruded cereal products of different flavour (cocoa, honey, chocolate) was carried out too. In analyzed samples the highest content of total phenolics and total flavonoids was measured in wheat germs. Especially in wheat germs and also in buckwheat and oat flakes, maize brans and cereals products Teddy (cereal balls with cocoa) and Ferda (cereal grains with honey) high levels of individual catechins, phenolic acids and flavonoids were determined too. The quantity of phenolic substances increased for several times in samples processed by acid hydrolysis in comparison to non-hydrolyzed samples. The high content of total saccharides, reduced saccharides and individual mono- and disaccharides was found mainly in extruded products. Concentration of monosaccharides increased in acid hydrolyzed samples in spite of disaccharides concentration that was higher only in some of hydrolyzed samples. In several cases final disaccharide concentrations were lower in hydrolyzed samples than in non-hydrolyzed ones.
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Analysis of biologically active substances in some cereal products
Valentová, Radka ; Starečková, Terezie (referee) ; Márová, Ivana (advisor)
Presented bachelor thesis is focused on study of biologically active substances in cereal products. In theoretical part over view of cereal active substances, predominantly phenolic compounds were introduced. In practical part 15 kinds of cereal products were analyzed. In these materials some group parameters - total phenolics, total flavonoids and total antioxidant activity were measured by spectrophotometry. RP-HPLC/UV-VIS method was performed for analysis of selected individual flavonids. The highest content of phenolic compounds was measured in cereals containing fruits (raspberries, blueberries, tropical and red fruit), cacao, crusty fruits (hazel nuts, sunflower seeds) and buckwheat. All cereal products contain catechine, epicatechine, catechin gallate, epicatechin gallate, chlorogenic and ferulic acid. As a part of bachelor thesis simple sensory analysis was performed and consumer questionnaires were evaluated.
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Fortification of selected cereal products
Hurtová, Jana ; RNDr.Renata Mikulíková, Ph.D. (referee) ; Márová, Ivana (advisor)
Present diploma thesis describes the study of bioactive compounds in the cereals. The work is focused on possible fortification of cereal products in order to increase nutritional value of final products which is reduced during the food processing and storage. Cereal grains are rich in several phenolic compounds, vitamins and minerals that reduce the risk of chronic diseases. The aim of this study was the preparation and analysis of model fortified cereals using lyophilized fruit originating from Czech Republic. A comparative analysis of content of bioactive substances in commercial and fortified products for children was performed too. The experimental part deals with a content of individual flavonoids by RP-HPLC/UV/VIS method, spectrophotometric determination of total and reducing saccharides and analysis of mono- and disaccharides by the HPLC/RI method as well. Differences in the content of individual flavonoids and saccharides after the application of acid hydrolysis of samples were investigated. The content of these compounds increased in most products because of their release from glycosidic forms. Presence of phenolics was confirmed in all analyzed cereals. Addition of 10% of lyophilized fruit/vegetable preparative (carrot, berries, apples) caused several fold increase of phenolics content in model mixtures. In commercially available cereal products there are relatively high differences in total phenolics content, proportionally to fruit component amount. The work included the spectrophotometric analysis of total polyphenols and flavonoids in a model physiological environment (artificial stomach juice) in which the hydrolysis of bound phenolic compounds occurred. The results of this study show that addition of lyophilized fruit seems to be a good way to increase the nutritional value and maintain the content of bioactive compounds in cereal products.
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Možnosti využití sladu pro sportovní výživu
Mišúnová, Lucie
The diploma thesis on “Possibilities of using malts for sports nutrition“is focused on the production of malts and their use in sports supplements. The theoretical part is devoted to individual cereals and pseudocereals, their nutritional composition, individual nutri-ents and their importance in nutrition and some possible products for sports nutrition. The practical part includes the production of single malts from selected cereals and pseudocereals and the production of experimental products that could have applications in sports nutrition. The products were then analysed for sensory analysis and nutritional value was determined.
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Development of fortified gluten-free cereals for specific nutrition
Dohnalová, Radka ; Fialová, Lenka (referee) ; Márová, Ivana (advisor)
The bachelor thesis was focused on the development of enriched gluten-free cereals for special nutrition. The fortified cereal product included processed microbial biomass, either as a freeze-dried powder or as an extract, for which the phenolic content, antioxidant content and protein content were determined. The theoretical part includes findings from professional literature on gluten-free cereals, pseudocereals and their chemical composition. Subsequently, a review on microalgae and yeasts was prepared including a list of their metabolites. The literature search focused on green microalgae and carotenogenic yeasts. In the experimental part, the characterization of the selected pseudocereals and optimization of the prepared extracts of the selected microalgae and carotenogenic yeast were firstly carried out. The selected pseudocereals were amaranth, buckwheat and quinoa. The green microalgae strain Chlamydomonas reinhardtii and the carotenogenic yeast strain Cystofilobasidium macerans were selected for enrichment of the pseudocereals. Carbohydrates, proteins, fatty acids, -glucans, gluten, vitamins, phenolic substances, flavonoids and antioxidants were determined in the pseudocereals. Total fatty acids, lipophilic substances, phenolic substances and total antioxidant activity were detected in the microbial biomass. Finally, mixed cereal products were prepared from pseudocereal flour, microbial biomass and microbial extract. The cytotoxicity of the selected extracts was determined by MTT assay. It was found that the addition of algal biomass alone or algal extract to cereal flours resulted in a significant increase in protein. The yeast ethanol extract increased the phenolic and antioxidant content of the cereal products.
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Význam pseudocereálií ve výživě české populace
Šišmová, Barbora
The study „The importance of pseudocereals in the nutrition of Czech population“ is focused on the characteristics of cereals and pseudocereals, their chemical composition, nutritional value and effects on the human organism. It describes the possibilities of their technological processing and the resulting products from selected types of pseudocereals.
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