Czech Journal of Food Sciences, 2006 (vol. 24), issue 1
Biosynthesis of food constituents: Amino acids: 1. The glutamic acid and aspartic acid groups - a review
Jan Velíšek, Karel Cejpek
Czech J. Food Sci., 2006, 24(1):1-10 | DOI: 10.17221/3287-CJFS 
This review article gives a survey of principal pathways that lead to the biosynthesis of the proteinogenic amino acids of the glutamic acid group (glutamic acid, glutamine, proline, arginine) and aspartic acid group (aspartic acid, asparagine, threonine, methionine, lysine, isoleucine) starting with oxaloacetic acid from the citric acid cycle. There is an extensive use of reaction schemes, sequences, and mechanisms with the enzymes involved and detailed explanations using sound chemical principles and mechanisms.
Determination of the contents of A- and B-starches in barley using Low Angle Laser Light Scattering
Ivan Bohačenko, Josef Chmelík, Vratislav Psota
Czech J. Food Sci., 2006, 24(1):11-18 | DOI: 10.17221/3288-CJFS
A method was proposed for the determination of the contents of A- and B-starches in barley and for the use in plant breeding stations and brewing/malting laboratories. A combination was used of classical methods (incl. crushing of barley kernels by a roll crusher, steeping in 0.02M HCl, repeated rubbing and filtering through the sieve of 0.08 mm), and novel pieces of know-how (treatment with β-glucanase and cellulase, alkalisation at pH = 10.0 and centrifugation of crude starch suspension through the layer of CsCl). In this way, barley starch of high purity was obtained at a very low loss, using Low Angle Laser Light Scattering for the determination...
Chemoprotective Effects of Broccoli Juice Treated with High Pressure
Lucie Mandelová, Jiří Totušek
Czech J. Food Sci., 2006, 24(1):19-25 | DOI: 10.17221/3289-CJFS
We investigated chemoprotective effects of broccoli juice, treated with high pressure method, using 500 MPa for a period of 10 minutes. By the use of this method, the conservation of nutritionally important substances occurs (for example vitamins, polyphenolic compounds, glucosinolates and other constituent substances). We followed the inhibition of mutagenicity of the model mutagen, N-nitroso-N-methylurea (MNU), by means of in vivo micronucleus test. After fourteen-day application of broccoli juice (0.2 ml/10 g of body weight of mouse) and after a single administration of MNU mutagen (50 mg/kg), a statistically significant decrease (p...
The sensory characteristics of berry-flavoured kefir
Lütfiye Yilmaz, Tülay Özcan Yilsay, Arzu Akpinar Bayizit
Czech J. Food Sci., 2006, 24(1):26-32 | DOI: 10.17221/3290-CJFS
Certain physicochemical and sensory characteristics of the flavoured kefir drink were studied during refrigerated storage. Kefir drink batches were prepared using 2% addition of kefir grains, incubation for 18 h and subsequent filtration. The batches were then flavoured with blackberry, raspberry and strawberry aromas in the concentrations of 0.05, 0.10 and 0.15%, respectively. The samples were taken for analysis on 1st, 4th, 7th, and 10th days of storage at 4 ± 1°C. The sensory analysis of the flavoured kefir samples revealed the best acceptability level on the 4th day of storage. Nevertheless,...
Fungal contamination and the levels of mycotoxins (Don and Ota) in cereal samples from poland and east slovakia
Eva Čonková, Anna Laciaková, Igor Štyriak, Ludwik Czerwiecki, Grażyna Wilczyńska
Czech J. Food Sci., 2006, 24(1):33-40 | DOI: 10.17221/3291-CJFS
The cereal samples were taken immediately after harvest from the selected localities of Poland(45 samples) and East Slovakia(60 samples). Fungal contamination of these samples was investigated and subsequently the presence of two important mycotoxins, deoxynivalenol (DON) and ochratoxin A (OTA), was quantitatively examined. Concerning mould contamination, no difference was observed between the samples from Polandand East Slovakia. The highest incidence was observed of Fusarium, Aspergillus, and Penicillium genera. However, most of the investigated samples of wheat, rye, and barley contained less than 104 cfu/g. The limit...
Separation of low molecular weight rapeseed proteins by RP-HPLC-DAD - a short report
Agnieszka Kosińska, Uttam D. Chavan, Ryszard Amarowicz
Czech J. Food Sci., 2006, 24(1):41-44 | DOI: 10.17221/3292-CJFS
Low molecular weight proteins were extracted and isolated from rapeseed and analysed using the HPLC-DAD method. The separation of proteins and phenolic compounds was done on the reversed phase C18 column with a gradient of acetonitrile in water. The chromatogram was characterised by two peaks of low molecular weight proteins with the retention times of 19.92 and 23.24 min. Additional three main peaks of phenolic constituents were recorded on the chromatogram. One of them with maximum of UV spectrum at 328 nm was identified as sinapic acid derivatives.