Czech Journal of Food Sciences, 2007 (vol. 25), issue 4
Fluorescence spectroscopy and chemometrics in the food classification - a review
Jana Sádecká, Jana Tóthová
Czech J. Food Sci., 2007, 25(4):159-174 | DOI: 10.17221/687-CJFS 
This review deals with the last few years' articles on various fluorescence techniques (conventional, excitation-emission matrix, and synchronous fluorescence spectroscopy) as a tool for the classification of food samples. Chemometric methods as principal component analysis, hierarchical cluster analysis, parallel factor analysis, and factorial discriminate analysis are briefly reminded. The respective publications are then listed according to the food samples: dairy products, eggs, meat, fish, edible oils, and others.
Trans-free fats with the products of the oil palm - a selective review
Kurt G. Berger
Czech J. Food Sci., 2007, 25(4):174-181 | DOI: 10.17221/688-CJFS
The results of nutritional research on fatty acids have led to the recommendation that the level of trans-fatty acids in foods (the products of partial hydrogenation of oils) should be reduced as far as possible. Palm oil and palm kernel oil are readily available and economical sources of solid fat. Formulae using oils to make fats for the main types of food products are reviewed.
Determination of polyphenols in beer by an effective method based on solid-phase extraction and high performance liquid chromatography with diode-array detection
Markéta Dvořáková, Petr Hulín, Marcel Karabín, Pavel Dostálek
Czech J. Food Sci., 2007, 25(4):182-188 | DOI: 10.17221/690-CJFS
The determination of polyphenols by spectrophotometric detection is complicated due to their low concentrations in beer. The beer samples have to be pre-concentrated before using the spectrophotometric detection for their quantification. An analytical method based on solid-phase extraction (SPE) and followed by high performance liquid chromatographic separation with diode-array detection is used for the determination of free gallic, protocatechuic, caffeic, p-coumaric, ferulic and salicylic acids, of (+)-catechin, (-)-epicatechin, and quercetin. These phenolic compounds participate in colloidal and sensory stability of beer. Six different SPE cartridges...
Prediction of the kind of sprouts of Cruciferae family based on artificial neural network analysis
Adam Buciński, Henryk Zieliński, Halina Kozłowska
Czech J. Food Sci., 2007, 25(4):189-194 | DOI: 10.17221/734-CJFS
The aim of this work was to show that artificial neural networks (ANNs) are a convenient tool for predicting the kind of sprouts originated from Cruciferae family. For this purpose, the known contents of bioactive compounds of small radish, radish, white mustard, and rapeseed seeds and sprouts were used for the prediction of the kind of a specific sprout. The input data reflected the contents of the following compounds in cruciferous seeds in the course of germination: soluble proteins (SP), ascorbic acid (AH2), total glucosinolates (GLS), reduced glutathione (GSH), and tocopherols (α-T, β-T, γ-T, δ-T), expressed...
Occurrence of squalene and cholesterol in various species of Czech freshwater fish
Zdenka Kopicová, Slavomíra Vavreinová
Czech J. Food Sci., 2007, 25(4):195-201 | DOI: 10.17221/733-CJFS
The triterpenoid hydrocarbon squalene, C30H50, abundantly occurring in nature, is known as a substance with a high anti-tumour activity proven by a number of research studies. A high content of squalene was found mainly in shark liver oil and also in olive oil and amaranth seed oil. Our work was aimed at examining squalene contents in fresh water fish. Altogether 20 fish species were analysed. Squalene was determined in the unsaponifiable matter of muscular and visceral fat by a capillary gas chromatography method using a flame ionisation detector; the analysis of the unsaponifiable matter was augmented by cholesterol assay. The...
Survival characteristics of E. coli O157:H7, S. typhimurium and S. aureus during kefir fermentation
Nural Karagözlü, Cem Karagözlü, Bülent Ergönül
Czech J. Food Sci., 2007, 25(4):202-207 | DOI: 10.17221/685-CJFS
In this research, the growth and survival of E. coli O157:H7, Salmonella typhimurium and Staphylococcus aureus were investigated during kefir fermentation. Two different levels of inoculation of the strains were conducted; the levels of 102 CFU/ml (EC-1, SA-1 and S-1) and 103 CFU/ml (EC-2, SA-2 and S-2). At 0, 2, 6, 12, and 24 hours of kefir fermentation at 23 ± 1°C, samples were taken and the counts of E. coli O157:H7, S. typhimurium, and S. aureus were determined. EC-1 grew from 2.29 ± 0.02 log CFU/ml to 4.13 ± 0.18 log CFU/ml whereas EC-2 grew from 3.22 ± 0.04 log CFU/ml to 6.78...
Dry heat inactivation of Bacillus cereus in rice
Milan Houška, Karel Kýhos, Aleš Landfeld, Jiřina Průchová, Ljuba Schlemmerová, Hana Šmuhařová, Vladimír Špelina, Pavla Novotná
Czech J. Food Sci., 2007, 25(4):208-213 | DOI: 10.17221/692-CJFS
The aim of this work was to validate the method of decontamination of rice at the temperature of 120°C (determined as optimal in previous experiments). Bacillus cereus was selected as the marker micro-organism for the monitoring of decontamination. The spores of Bacillus cereus are moderately heat resistant. In order to show the efficacy of our decontamination process, we artificially contaminated the rice under study with B. cereus. Decontamination was carried out in a homogenising steriliser about 20 h after contamination. The sample was first heated to 90°C and held at this temperature for 70 minutes. Then the temperature was...
Detection of pathogenic Yersinia enterocolitica serotype O:3 by biochemical, serological, and PCR methods
Jana Simonová, Miroslava Vázlerová, Iva Steinhauserová
Czech J. Food Sci., 2007, 25(4):214-220 | DOI: 10.17221/686-CJFS
In this study, the pathogenic Y. enterocolitica of serotype O:3 was monitored. The serotype is widely spread in Europe and has been linked to human yersiniosis. For the detection of pathogenic strains were used biochemical and serological methods as well as PCR methods based on the identification of virulence genes (ail, rfbC, ystA, yadA, virF). The occurrence of Y. enterocolitica O:3 strains was monitored in slaughter animals from a number of farms in the Czech Republic. A total of 3748 samples were collected coming from pigs (1388), cattle (633), poultry (902), and slaughter facilities (825). Fifty-two...
Determination and occurrence of bisphenol A, bisphenol A diglycidyl ether, and bisphenol F diglycidyl ether, including their derivatives, in canned foodstuffs' from the Czech retail market
Jan Poustka, Lenka Dunovská, Jana Hajšlová, Kateřina Holadová, Ivana Poustková
Czech J. Food Sci., 2007, 25(4):221-229 | DOI: 10.17221/689-CJFS
A several-year survey (2000-2006) documents a continuing occurrence of bisphenol A (BPA), bisphenol A diglycidyl ether (BADGE), and bisphenol F diglycidyl ether (BFDGE), including their derivatives, migrating from packaging into food. A wide range of bisphenols levels (from traces up to hundreds µg/kg) in canned foodstuffs available at the Czech retail market was found. An analytical procedure suitable for routine monitoring of bisphenols in various matrices was validated. Crude extracts (obtained by dichloromethane extraction in ultrasonic bath) were purified by gel permeation chromatography (GPC), identification/quantification was carried out...