Czech Journal of Food Sciences, 2008 (vol. 26), issue 3
Buckwheat grains and buckwheat products - nutritional and prophylactic value of their components - a review
Karolina CHRISTA, Maria SORAL-ŚMIETANA
Czech J. Food Sci., 2008, 26(3):153-162 | DOI: 10.17221/1602-CJFS 
Buckwheat is introduced into the diet as an alternative crop of renewed interest due to its nutritive and health-promoting value. Experiments with animal models have demonstrated that buckwheat flour may alleviate diabetes, obesity, hypertension, and hypercholesterolemia. A number of nutraceutical compounds exist in buckwheat grains and other tissues. These are a rich source of starch, proteins, antioxidants, and dietary fibre as well as trace elements. The biological value (BV) of buckwheat proteins is comparable to BV of other protein sources. Besides high-quality proteins, buckwheat grains contain some components with prophylactic value: flavonoids,...
Antioxidant activity, β-glucan and lipid contents of oat varieties
Lucia Brindzová, Milan Čertík, Peter RAPTA, Michal Zalibera, Anna Mikulajová, Mária Takácsová
Czech J. Food Sci., 2008, 26(3):163-173 | DOI: 10.17221/2564-CJFS
The antioxidant activity, total phenolic and β-glucans contents, and the fatty acid profile of total lipids in covered (black and yellow) and naked oats were studied. Oats with black hulls showed a significantly higher antioxidant activity in 2,2'-azino-di-[3-ethylbenzthiazoline sulphonate] (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) based tests in comparison to the grains with yellow hulls and those of the naked varieties. Radical scavenging activity of oats determined by electron paramagnetic resonance (EPR)/spin-trapping test did not depend on the colour of the grain hulls, but the naked grains showed a lower ability in scavenging reactive...
Antimicrobial properties of some essential oils against some pathogenic microorganisms
Nazan Celikel, Gökhan Kavas
Czech J. Food Sci., 2008, 26(3):174-181 | DOI: 10.17221/1603-CJFS
Investigations were carried out to assess the efficiency of five plant essential oils: thyme, myrtle, laurel, sage, and orange oils as natural food preservatives. The effect of the plant essential oils against Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Candida albicans at concentrations of 5-20 µl/disk (diameter 6 mm) and 0.5-3% (v/v) was studied in agar diffusion test medium and milk medium. The essential oils of these extracts exhibited markedly antibacterial and bacteriostatic activity, with thyme showing the highest inhibition and orange the lowest. However, with thyme extract, high inhibitory...
Distribution of major polyphenolic compounds in vine grapes of different cultivars growing in South Moravian vineyards
Ondřej Mikeš, Naděžda Vrchotová, Jan Tříska, Marie Kyseláková, Jan Šmidrkal
Czech J. Food Sci., 2008, 26(3):182-189 | DOI: 10.17221/1591-CJFS
The main chemoprotective polyphenolic compounds in the Vitis vinifera berries, rachis, and pedicels of 10 cultivars classified for the production of wine and growing in Southern Moravian vineyards, the Czech Republic, were studied. The following compounds were determined in the frozen fresh berries: gallic acid (1.8-13.3 mg/kg), catechin (70.3-659.1 mg/kg), epicatechin (67.1-237.2 mg/kg), trans-resveratrol (0.1-1.5 mg/kg), and pterostilbene (in traces); in the freeze-dried rachis and pedicels: rutin (10.5-68.6 mg/kg), isoquercitrine (29.8-218.3 mg/kg), catechin (283.7-2227 mg/kg), epicatechin (47.2-215.2 mg/kg), trans-resveratrol...
Rheological and sensory characteristics of yoghurt-modified mayonnaise
Petr ŠTERN, Jan POKORNÝ, Alena ŠEDIVÁ, Zdeňka PANOVSKÁ
Czech J. Food Sci., 2008, 26(3):190-198 | DOI: 10.17221/2566-CJFS
Rheological and textural characteristics were studied in a set of 11 samples of yoghurt-modified mayonnaise at 15, 20, and 25°C. The rheometer Rheostress 300 was used to determine the static yield value, apparent viscosity, thixotropy, and elasticity. The sensory texture and flavour profiles were developed and determined in agreement with the respective international standards, using a group of selected and trained assessors. The yield value and apparent viscosity substantially decreased with increasing temperature, but thixotropy and sensory characteristics were not significantly affected by temperature. Linear and semilogarithmic relations were observed...
Prediction of the average surface heat transfer coefficient for model foodstuffs in a vertical display cabinet
Karel Hoke, Aleš Landfeld, Jiří Severa, Karel Kýhos, Rudolf Žitný, Milan Houška
Czech J. Food Sci., 2008, 26(3):199-210 | DOI: 10.17221/1590-CJFS
Calculations of transient temperatures of food products after they are transferred from a warm environment into a display cabinet, require data on the surface heat transfer coefficient (SHTC). There is no forced air flow in an ordinary display cabinet, so the energy transfer is achieved mainly by free convection, conduction to a supporting plate, and radiation. Theoretical analysis of the heat transfer to a cylindrical sample demonstrates the relative influences of these mechanisms. This work investigates the apparent surface transfer coefficients with metal models. Heated models were placed individually (bare) in containers with and without lids....
Functional bioactive compounds and biological activities of Spirulina platensis lipids
Mohamed Fawzy Ramadan, Mohsen Mohamed Selim Asker, Zeinab K. Ibrahim
Czech J. Food Sci., 2008, 26(3):211-222 | DOI: 10.17221/2567-CJFS
The compositions and concentrations of lipid classes, fatty acids, tocopherols were determined in the lipids from blue-green microalga Spirulina platensis. Total lipids (TL) recovered using chloroform: methanol (2:1, v/v) were found to be 163.5 g/kg (on dry weight basis). The level of neutral lipids was the highest, followed by glycolipids and phospholipids, respectively. Among TL and lipid classes, palmitic, γ-linolenic and linoleic acids were the dominating fatty acids. Compared to the neutral lipids, the polar fractions were generally characterised by higher percentages of saturated fatty acids. The recovered lipids were characterised...
Effect of juice clarification by flotation on the quality of white wine and orange juice and drink - Short Communication
Eleni SINDOU, Vasilios VAIMAKIS, Tiverios VAIMAKIS, Ioannis G. ROUSSIS
Czech J. Food Sci., 2008, 26(3):223-228 | DOI: 10.17221/2565-CJFS
White wines of Debina cultivar were made from musts clarified by flotation using nitrogen as foaming agent. Flotation using air as the foaming agent (must hyperoxidation), without SO2 addition, was also applied. Turbidity and suspended solids were lower in must clarified by flotation using nitrogen than in that clarified by sedimentation (control). Flotation with hyperoxidation led to a reduction of must phenolics. All experimental wines exhibited similar gross compositions (alcohol, reducing sugars, total acidity, and volatile acidity). Wines made from musts clarified by flotation using nitrogen had similar total phenolic content, browning...