Czech Journal of Food Sciences, 2011 (vol. 29), issue 6
Indec of Volume 29
editors
Czech J. Food Sci., 2011, 29(6):I-XIX | DOI: 10.17221/3949-CJFS 
Microbiological measurements for the development of a new preservation procedure for liquid egg
Csaba Németh, Balázs Mráz, László Friedrich, Ágnes Suhajda, Béla Janzsó, Csaba Balla
Czech J. Food Sci., 2011, 29(6):569-574 | DOI: 10.17221/362/2010-CJFS
Since recently, the food industry has been increasingly using ready-to-process egg products as the basic materials instead of shell eggs. Subsequent to breaking shell eggs and completing pasteurisation, they are put on the market as liquid egg products or in powdered form as dried eggs. Consumers prefer liquid eggs which better preserve the advantageous properties of natural eggs, however, their shelf life is short with quick spoilage. We have examined, how long heat treatment is needed at temperatures below pasteurisation to influence the microbiological status of liquid egg products and in this way also their shelf life. A significant difference...
Antioxidant and antimicrobial activities of beet root pomace extracts
Jasna M. Čanadanović-Brunet, Sladjana S. Savatović, Gordana S. Ćetković, Jelena J. Vulić, Sonja M. Djilas, Siniša L. Markov, Dragoljub D. Cvetković
Czech J. Food Sci., 2011, 29(6):575-585 | DOI: 10.17221/210/2010-CJFS
We described the in vitro antioxidant and antimicrobial activities of ethanol, acetone, and water extracts of beet root pomace. Total contents of phenolics (316.30-564.50 mg GAE/g of dry extract), flavonoids (316.30-564.50 mg RE/g of dry extract), betacyanins (18.78-24.18 mg/g of dry extract), and betaxanthins (11.19-22.90 mg/g of dry extract) after solid-phase extraction were determined spectrophotometrically. The antioxidant activity was determined by measuring the reducing power and DPPH scavenging activity by spectrometric metod, and hydroxyl and superoxide anion radical scavenging activity by ESR spectroscopy. In general, the reducing...
Process optimisation of vacuum drying of onion slices
Jayeeta Mitra, Shanker Lal Shrivastava, P. Srinivasa Rao
Czech J. Food Sci., 2011, 29(6):586-594 | DOI: 10.17221/162/2010-CJFS
Dehydration of untreated and pre-treated onion slices under vacuum was optimised using the response surface methodology. The effects of the drying temperature (50-70°C), slice thickness (1-5 mm), and treatment (5% NaCl and 0.2% K2S2O5) were observed on the responses, viz. final moisture content, colour change, flavour content, and rehydration ratio of the dehydrated onion slices. Full factorial design was employed for the analysis. Optimisation of the vacuum drying process was achieved based on the criteria of maximum flavour retention, 3-3.5% db moisture content, acceptable colour, and rehydration ratio using numerical...
Vis/NIR hyperspectral imaging for detection of hidden bruises on kiwifruits
Qiang Lü, Ming-jie Tang, Jian-rong Cai, Jie-wen Zhao, Saritporn Vittayapadung
Czech J. Food Sci., 2011, 29(6):595-602 | DOI: 10.17221/69/2010-CJFS
It is necessary to develop a non-destructive technique for kiwifruit quality analysis because the machine injury could lower the quality of fruit and incur economic losses. Bruises are not visible externally owing to the special physical properties of kiwifruit peel.We proposed the hyperspectral imaging technique to inspect the hidden bruises on kiwifruit. The Vis/NIR (408-1117 nm) hyperspectral image data was collected. Multiple optimal wavelength (682, 723, 744, 810, and 852 nm) images were obtained using principal component analysis on the high dimension spectral image data (wavelength range from 600 nm to 900 nm). The bruise regions were extracted...
Yeast assimilable nitrogen in South Moravian grape musts and its effect on acetic acid production during fermentation
Mojmír Baroň
Czech J. Food Sci., 2011, 29(6):603-609 | DOI: 10.17221/259/2010-CJFS
We observed the content of yeast assimilable nitrogen in grape musts, its consumption by yeasts during fermentation, and acetic acid production. The experiments were performed in the years 2007 and 2008. The experimental variants involved 48 musts and wines originating fromSouthern Moravia. The data enabled to monitor the contents of yeast assimilable nitrogen in musts and to draw the general conclusion that these musts contain high concentrations of both ammonium ions and yeast assimilable nitrogen (124.4 mg/l and 257.8 mg/l, respectively), thus posing no danger of problems with the nutrition of yeasts in the course of fermentation. Also, the average...
Microbial transformation of citral by Aspergillus niger-PTCC 5011 and study of the pathways involved
Akbar Esmaeili, Shamila Rohany, Shila Safaiyan, Seyed Amir Zarei
Czech J. Food Sci., 2011, 29(6):610-615 | DOI: 10.17221/237/2009-CJFS
Citronellol and hydroxy citronellal are fragrance ingredients used in decorative cosmetics and fine fragrances. They have many applications in flavourings, extracts, foods, and drugs manufacturing. Their use worldwide is in the range exceeding 1000 metric tons per annum. Previous studies investigated the biotransformation of citral by the free cell method and immobilised cell method with Saccharomyces cerevisae. In this research, the microbial transformation of citral by the sporulated surface cultures method with Aspergillus niger-PTCC 5011 was studied. In experiments, A. niger was inoculated on solid media in conical flasks....
Preparation and characterisation of food grade chitosan from housefly larvae
Ai-Jun Zhang, Qi-Lian Qin, Huan Zhang, Hong-Tuo Wang, Xuan Li, Lin Miao, Yi-Jun Wu
Czech J. Food Sci., 2011, 29(6):616-623 | DOI: 10.17221/100/2010-CJFS
The preparation and characterisation of food-grade chitosan from housefly larvae are reported. A refinement procedure was developed to remove larval mouth hooks from the primary chitosan product, which greatly improved the quality of the final product and simplified the production procedures. Different factors affecting chitosan preparation were studied and an orthogonal experiment was designed to determine optimal preparation conditions. When prepared under optimal reaction conditions, the end product was snow-white in colour, had a high deacetylation percentage, good viscosity, and a low ash content. The end product was characterised by Fourier transform...
Cadmium, lead, and mercury concentrations in tissues of roe deer (Capreolus capreolus L.) and wild boar (Sus scrofa L.) from Lowland Croatia
Emil Srebočan, Andreja Prevendar Crnić, Ana Marija Ekert-Kabalin, Maja Lazarus, Jasna Jurasović, Kristijan Tomljanović, Doroteja Andreić, Ivančica Strunjak Perović, Rozelinda Čož-Rakovac
Czech J. Food Sci., 2011, 29(6):624-633 | DOI: 10.17221/249/2010-CJFS
Cadmium, lead, and mercury concentrations were determined in roe deer and wild boar tissues (muscle, liver, kidney) of three different age groups from lowland Croatia. Cadmium concentrations in the examined tissues increased with age in both species, being the highest in the kidney, and higher in roe deer as compared to wild boar. Lead concentration was higher in younger animals in comparison with both older groups. Contrary to the expectations, roe deer tissues revealed mostly higher lead concentrations than those of wild boar. Mercury concentration in the tissues of the animals examined was relatively low and no correlation with age was found. However,...
Simultaneous determination of chloride, bromide and iodide in foodstuffs by low pressure ion-exchange chromatography with visible light detection
Lingyun Yu, Xinshen Zhang, Jing Jin, Shujuan Che, Lan Yu
Czech J. Food Sci., 2011, 29(6):634-640 | DOI: 10.17221/216/2009-CJFS
An ion-exchange chromatography method with visible light detection was developed for the simultaneous determination of chloride, bromide, and iodide in foodstuffs. They were separated by means of low pressure ion-exchange chromatography using 4.0mM sodium carbonate solution as the eluent and a low pressure ion-exchange chromatography column as the separation column. The detection limits of chloride, bromide and iodide were 0.011 mg/l, 0.002 mg/l, and 0.023 mg/l, respectively. The relative standard deviations (RSDs) of the peak area were smaller than 2.9%. The recoveries were between 98.61% and 105.65%. Unlike the traditional methods, this validated...
Fluoroquinolone residues in raw cow's milk
Pavlína Navrátilová, Ivana Borkovcová, Jana Vyhnálková, Lenka Vorlová
Czech J. Food Sci., 2011, 29(6):641-646 | DOI: 10.17221/22/2011-CJFS
The aim of the study was to monitore the levels of fluoroquinolone residues in bulk samples of raw cow's milk. The bulk samples of raw cow's milk (n = 150) were obtained from 58 different milk suppliers in the South Moravian and Vysočina Regions. The samples were analysed by reverse phase high-performance liquid chromatography method with fluorescence detection and gradient elution. 87.3% of the raw milk samples were positive for the fluoroquinolones residues. Flumequine was present in none of the samples. The levels of other fluoroquinolones investigated were below the recommended maximum residue limit. The results of the study indicate that...
Survival of Mycobacterium avium subsp. hominissuis in homemade smoked pork sausages
Petr Králík, Hana Přikrylová Vondrušková, Iva Slaná, Monika Morávková, Ivo Pavlík
Czech J. Food Sci., 2011, 29(6):647-653 | DOI: 10.17221/444/2010-CJFS
We assessed the survival of Mycobacterium avium subsp. hominissuis (MAH) in artificially contaminated homemade smoked sausages prepared from pork meat according to traditional recipes, the effect of storage of such sausages at -20°C for three months on MAH viability and to compare assessment of MAH viability/presence by culture and qPCR. Three isolates of MAH were inoculated into the sausage mixture at concentrations of 106 CFU per gram of meat and cold smoked at 40°C for 12 h or hot smoked at 70°C for 6 hours. MAH survived the cold smoking procedure without any significant...
Antibiotic resistance of Enterococcus species isolated from raw foods of animal origin in South West part of Slovakia
Miroslav Kročko, Margita Čanigová, Viera Ducková, Anna Artimová, Jana Bezeková, Jennifer Poston
Czech J. Food Sci., 2011, 29(6):654-659 | DOI: 10.17221/246/2010-CJFS
We determined the prevalence and antibiotic resistance of enterococci isolated from raw foods of animal origin. All samples were positive for enterococci. The lowest count of enterococci was found in pork (2.00 log CFU/cm2), while bryndza cheese contained the highest count (4.99 log CFU/g). Among the 349 Enterococcus isolates, 49% were E. faecalis, 29% E. faecium, and 13% Enterococcus spp. Tetracycline and gentamicin resistance was the most common. We found the highest tetracycline resistance levels (91%) in isolates from poultry samples. The isolates from the poultry samples also displayed multidrug resistance...
Prof. Ing. Jan Pokorný, DrSc., Member of the Editorial Board of our journal, passed away
J. Davídek, J. Velíšek
Czech J. Food Sci., 2011, 29(6):660 | DOI: 10.17221/457/2011-CJFS