Presented diploma thesis is focused on analysis of selected biologically active substances in different kinds of natural and peeled rice. In rice samples phenolic compounds, antioxidant activity, content of saccharides and vitamin C were analysed. Active substances and saccharides were analysed by UV-VIS spectrophotometry and RP-HPLC-UV/VIS. Content of phenolic compounds and saccharides was measured before and after acid hydrolysis. The content of these compounds increased several times because of release of active substances from glycosides. As a part of diploma thesis basic sensory analysis was performed and consumer questionnaires were evaluated. The highest level of antioxidant activity was detected in Indian Wild rice. The highest content of total polyphenols and flavonoids was detected in Red Rice Natural before acid hydrolysis. After acid hydrolysis the highest content was detected in Indian Wild rice. The highest content of individual flavonoids, phenolic acids and catechins was detected in natural rice Indian Wild, Rice Three colours and in two samples of rice parboiled. The highest content of total and reducing saccharides was found in rice Indian Wild before hydrolysis, while after hydrolysis the content was very similar in all rice samples. The amount of individual monosaccharides after acid hydrolysis increased, while total content of disaccharides decreased. The highest value of simple sugars was detected in rice parboiled and Indian Wild rice. The content of vitamin C was detected only in four rice kinds - in two samples of rice parboiled, Rice Three colours and rice Indian Wild.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:216700 |
| Date | January 2011 |
| Creators | Valentová, Radka |
| Contributors | Melounová, Jitka, Márová, Ivana |
| Publisher | Vysoké učení technické v Brně. Fakulta chemická |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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