Czech Journal of Food Sciences, 2009 (vol. 27), issue 1
Furan in food - a review
Janka VRANOVÁ, Zuzana CIESAROVÁ
Czech J. Food Sci., 2009, 27(1):1-10 | DOI: 10.17221/2843-CJFS 
Furan and its derivatives were identified in a small number of heat-treated foods back in the 60's and 70's. In May 2004, US Food and Drug Administration published a report on the occurrence of parent furan in a number of thermally treated foods. Since furan has been classified as "possibly carcinogenic to human" by IARC, a great concern has been addressed to the analysis of this substance naturally-occurring in food. This paper gives a short overview on the mechanistic pathways of the parent furan formation in food by degradation of amino acids and/or reducing sugars, and oxidation of ascorbic acid and poly-unsaturated acids which can be induced by...
Immunohistochemical detection of soya protein - optimisation and verification of the method
Matej POSPIECH, Bohuslava TREMLOVÁ, Eva RENČOVÁ, Zdeňka RANDULOVÁ
Czech J. Food Sci., 2009, 27(1):11-19 | DOI: 10.17221/2848-CJFS
A functional immunohistochemical method for soya proteins detection was developed. The procedure is based on the avidin-biotin complex (ABC) method that attains sufficient sensitivity. The method was verified by the analysis of the model samples of different forms of soya additives containing various concentrations of soya isolate. The detection limit of soya present in the model samples was 0.5%. Different possibilities of the background staining were tested. The best results were obtained with the background staining according to Calleja. The results were confirmed by the accredited indirect ELISA method. The method allows the identification of various...
Strawberry jams: influence of different pectins on colour and textural properties
Mirela KOPJAR, Vlasta PILIŽOTA, Nela NEDIĆ TIBAN, Drago ŠUBARIĆ, Jurislav BABIĆ, Đurđica AČKAR, Maja SAJDL
Czech J. Food Sci., 2009, 27(1):20-28 | DOI: 10.17221/95/2008-CJFS
Colour and texture are very important quality properties of all foods. In this work, the influence was investigated of different types of pectin on colour and textural properties in strawberry jams and low-calorie strawberry jams containing fructose and aspartame or fructose syrup and aspartame. The highest anthocyanin content and total phenol content were detected in strawberry jam samples prepared with low methoxy amidated pectin. During storage, after 4 and 6 weeks at both storage temperatures, room temperature and 4°C, anthocyanin content and total phenol content decreased. Also, free radical scavenging activity decreased during storage. As far...
Phytate degradation during breadmaking: The influence of flour type and breadmaking procedures
Tomaž Požrl, Mirela Kopjar, Irena Kurent, Janez Hribar, Anja Janeš, Marjan Simčič
Czech J. Food Sci., 2009, 27(1):29-38 | DOI: 10.17221/130/2008-CJFS
Phytic acid has been considered to be an antinutrient due to its ability to bind minerals and proteins, either directly or indirectly, thus changing their solubility, functionality, absorption, and digestibility. In this study, the influence of the flour type (type 500, type 850, and whole meal flour) and three different breadmaking procedures (direct, indirect, and with sourdough addition) on phytic acid was investigated. The results showed that the flour type influenced the phytic acid content. The phytic acid contents of flour type 500, type 850, and whole meal flour was 0.4380, 0.5756, and 0.9460 g/100 g dm, respectively. The dough and bread prepared...
Trace elements species fractionation in rye flour and rye (Secale cereale L.) seedlings
Jan Polák, Oto Mestek, Richard Koplík, Jiří Šantrůček, Jana Komínková, Milan Kodíček
Czech J. Food Sci., 2009, 27(1):39-48 | DOI: 10.17221/33/2008-CJFS
The fractionation of Cd, Cu, Mo, Ni, and Zn species in extracts of rye (cv. Fernando) seedlings (grown up in both standard and Cd2+-enriched medium) and rye flour was performed by SEC/ICP-MS method. The majority of Cu, Zn, and Ni in all samples were bound in the 1-2 kDa fraction. Molybdenum occurred in all samples in the fraction of 3 kDa. During five days of cultivation in a solution of 30 µmol/l Cd2+, the plants accumulated as much as 5 mg/kg fresh matter of Cd, but its soluble portion represented only 12-15%. The prevailing portion of Cd complexes was contained in the fraction of 3 kDa, while the minor part occurred in...
Molecular cloning and characterisation of alpha subunit of H+-ATPase in Lactobacillus casei Zhang
Xia Chen, Mei Yang, Zhihong Sun, Wenjun Liu, Tiansong Sun, He Meng, Heping Zhang
Czech J. Food Sci., 2009, 27(1):49-54 | DOI: 10.17221/134/2008-CJFS
The acid tolerance is an important property of Lactic acid bacteria as potential probiotics. H+-ATPase is considered a key gene in several bacteria with the ability of acid tolerance. We cloned and sequenced the full length cDNA of alpha subunit of H+-ATPase gene in Lactobacillus casei Zhang, which had been isolated from traditional home-made koumiss in Inner Mongolia of China. The results showed that the respective cDNA sequence is composed of 1530 nucleotides and codes a putative protein including 509 amino acids. In addition, we also reconstructed the phylogenic trees for H+-ATPase gene based on amino acids...
Identification and characterisation of antimicrobial activity of nisin a produced by Lactococcus lactis subsp. lactis LL27
Pinar ŞANLIBABA, Nefise AKKOÇ, Mustafa AKÇELIK
Czech J. Food Sci., 2009, 27(1):55-64 | DOI: 10.17221/151/2008-CJFS
In this study, bacteriocin producing lactococcal strains were isolated from Turkish raw milk samples. Among these isolates, LL27 had the highest inhibition activity against Gram-positive indicator strains, and was selected for further analyses. DNA sequencing of 16S ribosomal RNA gene demonstrated that the isolate was Lactococcus lactis subsp. lactis. The gene encoding the bacteriocin in this strain was found to be identical to that of nisin A using direct PCR sequence methods. The bacteriocin was completely inactivated by α-chymotrypsin and proteinase K and partially inactivated by lipase and α-amylase. pH and heat stability...
In vitro fermentation of galactosyl derivatives of polyols by Lactobacillus strains
Elżbieta KLEWICKA, Robert KLEWICKI
Czech J. Food Sci., 2009, 27(1):65-70 | DOI: 10.17221/176/2008-CJFS
Probiotic lactic acid bacteria belonging to the species Lactobacillus casei, Lb. paracasei, and Lb. acidophilus were cultivated in the presence of galactosyl derivatives of erythritol, xylitol, and sorbitol, as well as the polyols themselves: erythritol, xylitol, sorbitol, lactitol, and glucose as a reference. After 48-h incubation, the profile of the main metabolic products (lactic and acetic acids) and the amount of the studied bacteria biomass were determined. It was found that none of the bacteria studied metabolised erythritol or xylitol. In the presence of these compounds, no increase of metabolic activity of the lactic fermentation...