Academic literature on the topic 'Cereální produkty'

Historically Triticum aestívum L. and Secale cereále L. are widely used in the production of bakery products. From the total volume of grain cultivated, roughly 85% is used for the manufacturing of flour, while the remaining part is discarded or utilized rather inefficiently. The limited value attached to bran is associated with their structural complexity, i.e., the presence of cellulose, hemicellulose, and lignin, which makes this material suitable mostly as a feed supplement, while in food production its use presents a challenge. To valorize these materials to food and pharmaceutical applications, additional pre-treatment is required. In the present study, an effective, sustainable, and eco-friendly approach to ferulic acid (FA) production was demonstrated through the biorefining process accomplished by non-starch polysaccharides degrading enzymes. Up to 11.3 and 8.6 g kg−1 of FA was released from rye and wheat bran upon 24 h enzymatic hydrolysis with multi-enzyme complex Viscozyme® L, respectively.

Acrylamide (AA) is a probable human carcinogen and undesirable contaminant which is produced by the reaction of reducing sugars with asparagine in plant foods during their thermal treatment above 120 °C. AA is most often determined by GC-MS and LC-MS/MS in isolates from the matrix in a wide range of foods. According to our observations, AA intake from food is higher among young people (from 1.8 to 3.8 µg/kg bw/day), which is consistent with the estimations of JECFA FAO/WHO from the year 2006. Considering the health risk, it is recommended to reduce AA formation in food during its processing, in particular exploiting the available experience. The aim of this thesis was to extend the knowledge of the possibility of AA elimination in selected types of thermally processed foods. The study was focused on cereal foods that contribute significantly to AA exposure, especially bread and sweet biscuits. The whole AA content in the bread is in the crust, which represents 5-15% of the bread. Crust of home-made bread contains approximately 30-75 µg/kg, however the marketed bread contains 2 to 10 times more of AA. This is due to the composition of bread mix, preparation conditions and baking. For maintaining the quality of home-made bread during the dry mixture shelf-life, optimization of bread mixtures was designed by increasing of yeast content, which proved positive effect on the reduction of AA content at sufficiently high activity of the yeast. Monitoring of AA content in assortment of sweet bakery products showed higher levels of AA in diabetic biscuits containing fructose instead of sucrose. Three of them even exceeded the reference value (500 µg/kg) more than 1.5 times for commodity "cookies". Elimination of AA by applications of the enzyme asparaginase has been designed for minimal interference in technology of their production. The concentration of the enzyme and the appropriate method of its use in industrial environment have been tested previously in model systems. In optimized conditions of the enzyme application, AA content in diabetic biscuits was reduced by more than 40% without affecting the organoleptic properties of the final product. Effect of the antioxidants on AA formation was also part of the study. AA content in gingerbread was reduced efficiently by the use of fennel, anise, cloves, vanilla and white pepper (by about 9-21%). Conversely, coriander and cinnamon significantly increased its content (by 18-54%). Since correlations between the DPPH• radical quenching activity of the spice extracts and AA content was not observed, the final content of AA was probably influenced by the chemical composition of spices and reactivity of the individual components in the matrix. Investigated methods appear to be suitable ways of elimination AA in some foods; however their specific use must be optimized with regard to the composition of the food, processing and the technology used. Estimated impact of application of the above-mentioned methods to the overall elimination of AA exposure showed that its intake in high school students from the Czech and Slovak Republic can be reduced on average by 10%. This decrease is a success to reduce the possible risk of cancer disease by eating foods with a high AA content. It is also important piece of information for food producers for further development of relevant methods for AA elimination which would help to reduce the AA intake from foods even more.

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.

The diploma thesis deals with the production of cereal goods, mainly cereal milk and cereal biscuits. The theoretical part describes particular cereals used in food processing industry. Integral part of this issue is description of malt and cereal manufacturing. Subsequently, the practical part provides comparison of several production experiments. Their outcomes were various cereal milk samples prepared from a variety of back fill oat malt and raw oat. The milk samples were then tested by sensory analysis. Besides the study of the cereal milk products, the other subject of the practical part is the production of cereal biscuits as well. The biscuits were made of many different combinations of barley and oat malt and raw oat. The production of biscuits was then followed by realization of sensory analysis again. For each analyzed sample was determined sensory profile, which was compared with others.

In the theoretical part of the diploma thesis there was described food of cereal character including school nutrition programmes and their representation in the diet of basic school pupils and university students. The interview focused on the representation of cereal products and their importance in the diet is described in the research part of this diploma thesis. The interview was made in the groups of pupils in higher basic schools and university students. When evaluating the questionnaire survey, there were assessed the quantity, individual types and quality of commonly consumed cereal products and the level of eating habits of respondents in accordance with the principles of good nutrition. After evaluation of the interviews it was found that basic school pupils have worse all-day eating habits than university students. It was confirmed mostly by the answers of the questions relating to breakfast, mid-afternoon snacks and total number of meals during a day. University students prefer wholegrain products more than basic school pupils. Pupils of higher basic schools have lower knowledge level of cereals than university students.