Czech Journal of Food Sciences, 2013 (vol. 31), issue 1
List of Reviewers - 2012
editors
Czech J. Food Sci., 2013, 31(1):I-II | DOI: 10.17221/6543-CJFS 
Comparison between thermal hydrolysis and enzymatic proteolysis processes for the preparation of tilapia skin collagen hydrolysatesOriginal Paper
Wei Wang, Zhonglei Li, Junzhong Liu, Yuejun Wang, Shanhong Liu, Mi Sun
Czech J. Food Sci., 2013, 31(1):1-4 | DOI: 10.17221/49/2012-CJFS
The tilapia (Oreochromis niloticus) skin hydrolysate was produced by thermal or enzymatic hydrolysis processes. Several product characteristics were studied such as the average molecular weight, 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, yield, and protein content, in order to compare thermal hydrolysis and enzymatic proteolysis processes for the hydrolysed tilapia skin collagen production. The effects of the following hydrolysis parameters (retorting time and pH, protease combination, and proteolysis time) were studied. Compared with the thermal hydrolysis process, the enzymatic proteolysis process needed less time and milder...
Antioxidant activity and mechanism of action of some synthesised phenolic acid amides of aromatic aminesOriginal Paper
Emma MARINOVA, Lubomir GEORGIEV, Iskra TOTSEVA, Katya SEIZOVA, Tsenka MILKOVA
Czech J. Food Sci., 2013, 31(1):5-13 | DOI: 10.17221/280/2011-CJFS
The antioxidative activities and mechanism of action were studied of eight synthesised cinnamoyl- and hydroxycinnamoyl amides of biogenic amines (caffeoyldopamine, cinnamoyldopamine, p-coumaroyldopamine, feruloyldopamine, sinapoyldopamine, caffeoylphenylethylamine, caffeoyltyramine, and caffeoyltryptamine) in a wide concentration range (2.5-20 × 10-4M) during autoxidation of triacylglycerols of sunflower oil. It was established that all amides exhibited excellent antioxidant activity, higher than or comparable with that of caffeic acid. The best activity was shown by caffeoyldopamine followed by cinnamoyldopamine and caffeoyltyramine....
Antibiotic resistance of enterococci, coagulase negative staphylococci and Staphylococcus aureus isolated from chicken meatOriginal Paper
Naci Erhan Yurdakul, Zerrin Erginkaya, Emel Ünal
Czech J. Food Sci., 2013, 31(1):14-19 | DOI: 10.17221/58/2012-CJFS
We determined the antibiotic resistance of enterococci, coagulase negative staphylococci, and Staphylococcus aureus isolated from chicken meat samples. The antibiotic resistance of the isolated strains was estimated by the Kirby-Bauer disk diffusion method (according to the NCCLS document M2-A9 suggestions). It was found that all strains of Enterococcus spp. were resistant to tetracycline, 75% of them were resistant to ciprofloxacin, and 50% of them were resistant to erythromycin, vancomycin, and chloramphenicol. Also all strains of S. aureus were resistant to tetracycline and 25% of S. aureus strains were resistant...
Effects of season and time of milking on spontaneous and induced lipolysis in bovine milk fatOriginal Paper
Renáta TOUŠOVÁ, Luděk STÁDNÍK, Jaromír DUCHÁČEK
Czech J. Food Sci., 2013, 31(1):20-26 | DOI: 10.17221/9/2012-CJFS
The effects were evaluated of different factors on the level of spontaneous (SPO) and induced (IND) lipolysis as defined by the content of free fatty acids (FFA) in milk. Milk samples were collected at monthly intervals throughout the year from both morning and evening milkings either individually in a milking parlour (SPO; n = 10) or from the bulk tank (IND; n = 10). The data were analysed using SAS 9.1. More intensive SPO was observed from March to May with higher FFA contents (+0.034 to +0.523 mmol/100 g of fat; P < 0.05-0.01), and also from September to November (+0.077 to +0.292 mmol/100 g of fat; P <...
Antimicrobial resistance of lactobacilli isolated from foodOriginal Paper
Marta DUŠKOVÁ, Renáta KARPÍŠKOVÁ
Czech J. Food Sci., 2013, 31(1):27-32 | DOI: 10.17221/110/2012-CJFS
Bacteria of the genus Lactobacillus are of great benefit in many areas of life. They are widely used in food industry, in particular as part of starter cultures for fermented dairy and meat products, but also in human and veterinary medicine as probiotics. The increasing global problem of antimicrobial resistance may also involve lactic acid bacteria because of the possible risk of resistance genes transfer. We determined the antimicrobial susceptibility of lactobacilli isolated from food. Ninety facultatively heterofermentative lactobacilli isolated from retail dairy and meat products were tested. The resistance to antimicrobials was screened...
Dynamics of 5-hydroxymethylfurfural formation in shortbreads during thermal processingOriginal Paper
Stanisław KOWALSKI, Marcin LUKASIEWICZ, Lesław JUSZCZAK, Edyta Maja KUTYŁA-KUPIDURA
Czech J. Food Sci., 2013, 31(1):33-42 | DOI: 10.17221/87/2012-CJFS
The analysis was carried out of 5-hydroxymethyl-2-furfural (HMF) formation during the baking of shortbreads. The investigation was done on three types of shortbread in which sucrose, glucose, or fructose were used as sweeteners. In all the samples the concentration of sugar was 20% (w/w). The cookies were baked in a laboratory oven at temperatures of 200, 215, 230, and 245°C. The samples for the HMF determination were taken at intervals from 5 to 18 min depending on the baking temperature. It was found that HMF formation can be described by exponential equation. The HMF formation was correlated with the colour changes of the cakes determined according...
Detection of genetically modified soya, maize, and rice in vegetarian and healthy food products in SerbiaOriginal Paper
Gordana Zdjelar, Zorica Nikolić, Ivana Vasiljević, Biljana Bajić, Dušica Jovičić, Maja Ignjatov, Dragana Milošević
Czech J. Food Sci., 2013, 31(1):43-48 | DOI: 10.17221/105/2012-CJFS
The presence of genetic modifications was analysed in a total of 100 samples of non-labelled vegetarian and healthy food products. The basic raw materials in the samples tested comprised maize, soya, and/or rice. The screening of all samples was performed using the primers for CaMV35S promoter. The positive samples from this initial screening were further subjected to the analysis of specific transgenic material to determine the type of GMO present with subsequent quantification. Roundup Ready soya was found in eight samples, but its content was below the limit of 0.9%. None of the analysed samples of food products contained GM maize and GM rice. Considering...
Effects of several sanitisers for improving quality attributes of minimally processed Fragaria vesca strawberryOriginal Paper
Sergio NOGALES-DELGADO, Ana María FERNÁNDEZ-LEÓN, Jonathan DELGADO-ADÁMEZ, María Teresa HERNÁNDEZ-MÉNDEZ, Diego BOHOYO GIL
Czech J. Food Sci., 2013, 31(1):49-54 | DOI: 10.17221/378/2011-CJFS
In order to decrease microbial contamination, fresh-cut industry commonly uses sodium hypochlorite as a disinfection agent, however, the by-products such as trihalometanes and chloramines are potentially harmful for human health making necessary the search for alternative disinfectant agents. A comparative study on the effectiveness of different disinfection methods on the quality of minimally processed F. vesca strawberry is presented. The fruit was processed in a clean room through the following steps: reception, cutting, washing, draining, and packaging. The processed strawberries were packaged in thermally sealed polypropylene trays using...
Isotachophoretic determination of glucosamine and chondroitin sulphate in dietary supplementsOriginal Paper
Eliška VÁCLAVÍKOVÁ, František KVASNIČKA
Czech J. Food Sci., 2013, 31(1):55-65 | DOI: 10.17221/107/2012-CJFS
Glucosamine and chondroitin sulfate, components of normal cartilage, are used as ingredients in dietary supplements intended to treat osteoarthritis and/or to support joint health. Of concern is the documented lack of quality in many of the marketed products. We present here a capillary isotachophoretic method for the determination of glucosamine and chondroitin sulfate in dietary supplements. Cationic analysis of glucosamine was performed with a leading electrolyte consisting of 10mM NH4OH + 20mM acetic acid. As the leading electrolyte for anionic analysis of chondroitin sulphate, a mixture of 5mM HCl + 10mM glycylglycine + 0.05% of 2-hydroxyethylcellulose...
Evaluation of physicochemical and sensory properties of ethanol blended with pear nectarOriginal Paper
Urszula Pankiewicz, Jerzy Jamroz
Czech J. Food Sci., 2013, 31(1):66-71 | DOI: 10.17221/400/2011-CJFS
Ten trained panelists evaluated the perceived density as well as the physical and perceived viscosities of the product obtained by blending ethanol with pear nectar. There was a link between the concentrations of ethanol in pure vodka and in its blend with the nectar, and the perceived sensory viscosity and the drink density. There was a very good (R2 = 0.9442) and poor (R2 = 0.6464) correlation, respectively, between the experimentally found density and viscosity and the perceived viscosity of aqueous ethanol. These properties of aqueous ethanol and alcohol pear drinks correlated very well (R2...
Investigating the effect of high hydrostatic pressure processing on anthocyanins composition of mulberry (Morus moraceae) juiceOriginal Paper
Narku Felix ENGMANN, Yong-Kun Ma, Xu YING, Ye QING
Czech J. Food Sci., 2013, 31(1):72-80 | DOI: 10.17221/530/2011-CJFS
Anthocyanins are potent natural antioxidants with acclaimed health benefits and are also used as industrial colourants. These functions are based on the types and amounts of anthocyanins present in the food material. We identified and characterised mulberry fruit anthocyanins before and after high hydrostatic pressure (HHP) treatment. Three separate samples were differently treated at 200, 400, and 600 MPa for 20 min, respectively. Anthocyanins were identified and characterised using high-performance liquid chromatography (HPLC), electrospray ionisation mass spectrometry (ESI/MS), and the literature data. Cyanidin-3-O-glucopyranoside (55.56%)...
Filbertone as a marker for the assessment of hazelnut spread qualityOriginal Paper
H. Čížková, A. Rajchl, J. Šnebergrová, M. Voldřich
Czech J. Food Sci., 2013, 31(1):81-87 | DOI: 10.17221/493/2011-CJFS
A method was proposed for the authenticity evaluation of the hazelnut based products, in which the hazelnut paste content is the principle qualitative parameter. The procedure is based on the determination of filbertone ((E)-5-methyl-hept-2-en-4-one), the natural, unique, and characteristic aroma component of the hazelnuts. A set of authentic hazelnut pastes and model samples containing various hazelnut paste amounts (from 0.1% to 28%) were analysed. Due to the variability found in filbertone content, it was not possible to propose a sufficiently robust model for the hazelnut paste quantification, however, filbertone was found to be a proper...
Improved detection of Ochratoxin A by marine bioluminescent bacteria V. harveyi BAOriginal Paper
Weifen WANG, Mingzhou ZHANG, Jiehong FANG, Linya ZHANG, Xiaonan ZOU, Xueyan WANG
Czech J. Food Sci., 2013, 31(1):88-93 | DOI: 10.17221/18/2012-CJFS
We applicate the bioluminescent assay system for evaluating the toxicity of Ochratoxin A (OTA). The optimum conditions for the growth and bioluminescence of V. harveyi BA were investigated, including NaCl concentration and pH in the medium, incubation temperature, and OTA action time. The growth and luminescence reached the perfect phase with the NaCl concentration in the range of 1% to 2%, pH 8-9, incubation temperature 25-30°C, and OTA acting for1 hour. Based on these optimum conditions for bioluminescence, the inhibitory effect of OTA on luminosity was pursued. When OTA concentration fell into the range of 0.1-1.0 µg/l, bioluminescence...
Low-pressure treatment to control food-infesting pests (Tribolium castaneum, Sitophilus granarius) using a vacuum packing machineOriginal Paper
Zuzana Kučerová, Karel Kýhos, Radek Aulický, Václav Stejskal
Czech J. Food Sci., 2013, 31(1):94-98 | DOI: 10.17221/154/2012-CJFS
Since recently, the food industry has been faced with serious problems regarding pest-infested food commodities and deregistration of many chemical biocides by the EU Biocide Directive. These conditions have created an urgent need for a physical method of protecting food against pests. Therefore, a vacuum packing machine was used for laboratory testing of the effectiveness of vacuum packaging on the mortality of the red flour beetle (Tribolium castaneum) and granary weevil (Sitophilus granarius) at different temperatures and exposure times. There were significant differences in the susceptibility to low pressure (vacuum) between the...