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Influence of storage at 4°C on the stability of high hydrostatic pressure treated onionOriginal PaperJosé L. VÁZQUEZ-GUTIÉRREZ, María HERNÁNDEZ-CARRIÓN, Amparo QUILES, Isabel HERNANDOCzech J. Food Sci., 2014, 32(1):96-101 | DOI: 10.17221/471/2012-CJFS The effects of refrigerated storage on the microstructure and physicochemical properties of high hydrostatic pressure (HHP) treated onion were evaluated. Onion was submitted to 100 MPa at 50°C or 400 MPa at 25°C for 5 min, and stored for 28 days at 4°C. Electron microscopy techniques and light microscopy were used for the microstructural study. Total soluble phenolics, soluble protein percentage, and shear force were also studied. HHP treatments affected the cell wall and membrane permeability, favouring the diffusion of soluble material to the apoplast. Storage at 4°C also caused important structural degradation in the HHP-treated samples, which was higher when 400 MPa at 25°C were applied and led to physico-chemical changes during the first week of storage. Interactions between phenolics and solubilised cell wall material or proteins could explain the decrease in soluble phenolics and proteins during storage. |
Composition and sensory analysis for quality evaluation of a typical Italian cheese: influence of ripening periodOriginal PaperPatrizia PAPETTI, Angela CARELLICzech J. Food Sci., 2013, 31(5):438-444 | DOI: 10.17221/447/2012-CJFS Caciottina massaggiata di Amaseno, a typical dairy product of the Lazio Region prepared from buffalo milk, was analysed for moisture, fat, protein, pH, and acidity content at different storage (0, 3, 6, and 9 months after production). Cheeses were also evaluated for various sensory attributes (taste, flavour, texture, and overall acceptability) during storage. We evaluated the flavour profile and acceptability of Caciottina cheeses of varying maturity using a descriptive analysis. Descriptive sensory profiles of selected cheeses were determined using a trained panel (n = 12) and an established cheese flavour sensory language. In quantitative descriptive analysis a trained panel rated the cheeses for colour, odour, taste and texture. In the affective tests the panellists evaluated the samples for overall quality. The results proved that months of production had significant effects on the sensory quality of the cheeses. |
Potentials of probiotics in the treatment of food allergy - a reviewReviewAmi PATEL, Nihir SHAHCzech J. Food Sci., 2014, 32(3):205-212 | DOI: 10.17221/200/2013-CJFS Food allergy is an adverse immune response to some proteins in some foods. Probiotic, health promoting bacteria have gained much importance because of their innumerable benefits, particularly in the treatment of diarrhea, hypercholesterolemia, atopic dermatitis, eczema, and gastrointestinal disorders by strengthening the immune system. The current paper reviews recent advances made in the treatment of food allergy through employing probiotic or synbiotic therapy. The results of several reports are very promising suggesting probiotics can influence the immune system to curtail the allergic responses. |
Stability of fried olive and sunflower oils enriched with Thymbra capitata essential oilOriginal PaperMaria G. MIGUEL, Maria D. ANTUNES, Abdulrahman ROHAIM, Ana Cristina FIGUEIREDO, Luís G. PEDRO, José G. BARROSOCzech J. Food Sci., 2014, 32(1):102-108 | DOI: 10.17221/217/2013-CJFS The stability of olive and sunflower oils for domestic uses after frying cow steak or only heating were evaluated in the presence or absence of the carvacrol-rich essential oil of Thymbra capitata. The treatments consisted of sunflower and olive oils either enriched with 200 mg/l of T. capitata oil or without it, heating at 180°C for 20 min, or frying 100 g cow steak at the same temperature and for the same period of time. In all assays, acid, peroxide, and p-anisidine values were followed over time. The fatty acid profile was estimated before heating or frying as well as at the end of the experiment. The results showed that the type of fat as well as the type of treatment (frying or heating) was determinant for the acid, peroxide, and p-anisidine values found. The presence of the essential oil also demonstrated to affect those values depending on the type of the oil as well as on the type of the treatment (frying or heating). In contrast, the fatty acid profile did not change greatly. |
Determination of anthocyanins in red grape skin by pressurised fluid extraction and HPLCBarbora HOHNOVÁ, Lenka ŠŤAVÍKOVÁ, Pavel KARÁSEKCzech J. Food Sci., 2008, 26(10):S39-S42 | DOI: 10.17221/243/2008-CJFS Grape anthocyanins not only play an important role in the colour quality of red wines but they also have many beneficial effects on human health, e.g., reduction of coronary heart disease incidence, or anticarcinogenic and antioxidant properties. Therefore, a rapid and efficient extraction technique prior to chromatographic analysis is of primary interest. Pressurised Fluid Extraction (PFE) presents a fast, effective, and environmentally friendly extraction method for the analysis of red grape pigments. In this study, PFE in static mode was utilised for the extraction of 3-monoglucoside anthocyanins from the grape skin of highly pigmented variety Alibernet. The effects of the type of the extraction solvent and the extraction temperature were studied. The identification of the above given compounds were performed by high-performance liquid chromatography with diode array detection (HPLC-DAD) based on Synergi C-12 column separation. The wavelength was set at 520 nm. All compounds were determined and identified during 50 minutes. |
Content of trans-resveratrol in leaves and berries of interspecific grapevine (Vitis sp.) varietiesPetra Bábíková, Naděžda Vrchotová, Jan Tříska, Marie KyselákováCzech J. Food Sci., 2008, 26(10):S13-S17 | DOI: 10.17221/238/2008-CJFS The aim of this project was to study changes in the content of trans-resveratrol in berries and leaves of grapevine (Vitis sp.) infested by fungal diseases, especially by Botryotinia fuckeliana Whetzel, called as grey mildew, Plasmopara viticola (Berk. & M.A. Curtis) Berl & De Toni, called downy mildew and Uncinula necator (Schw.) Burr, called powdery mildew. In our experiments two white and two blue varieties were used. Contents of trans-resveratrol were determined in healthy and infested leaves and in healthy berries. Infested leaves of white varieties contained more trans-resveratrol than those of blue varieties. The content of trans-resveratrol in berries was lower than that in leaves. |
Differentiation of Lactobacillus species by ARDRAOriginal PaperKateřina Kšicová, Marta Dušková, Renáta KarpíškováCzech J. Food Sci., 2013, 31(2):180-188 | DOI: 10.17221/125/2012-CJFS The Lactobacillus species by 16S Amplified Ribosomal DNA Restriction Analysis (16S-ARDRA) was identified. Lactobacilli are bacteria often found in foodstuffs of both animal and vegetable origins. On one hand, they play an important role in the food spoilage and, on the other hand, they are used as starter cultures in food fermentation processes. The species-specific identification by traditional biochemical methods is time consuming and not always fully effective. Therefore, more efficient techniques are searched for. We focused on rapid identification of Lactobacillus isolates from different habitats. Forty-nine collection strains and isolates belonging to the genus Lactobacillus were discriminated. ARDRA was carried out with two restriction endonucleases. For the comparison of similarity, the Jaccard coefficient and clustering by the unweighted pair group method with arithmetic averages (UPGMA) were used. The percentages of similarity between profiles varied from 22% to 100% (AluI) and from 27% to 100% (MspI). This method proved applicable to the differentiation of 10 species. |
Effect of juice clarification by flotation on the quality of white wine and orange juice and drink - Short CommunicationEleni SINDOU, Vasilios VAIMAKIS, Tiverios VAIMAKIS, Ioannis G. ROUSSISCzech J. Food Sci., 2008, 26(3):223-228 | DOI: 10.17221/2565-CJFS White wines of Debina cultivar were made from musts clarified by flotation using nitrogen as foaming agent. Flotation using air as the foaming agent (must hyperoxidation), without SO2 addition, was also applied. Turbidity and suspended solids were lower in must clarified by flotation using nitrogen than in that clarified by sedimentation (control). Flotation with hyperoxidation led to a reduction of must phenolics. All experimental wines exhibited similar gross compositions (alcohol, reducing sugars, total acidity, and volatile acidity). Wines made from musts clarified by flotation using nitrogen had similar total phenolic content, browning capacity, and organoleptic quality as the control wines. Wines made from musts clarified by flotation using air had lower total phenolic contents and browning capacity than were those in control wines. These wines were of well acceptable quality but exhibited a slightly oxidised aftertaste. The results indicate that flotation using nitrogen can be effective in the production of typical Debina wine, while flotation using air may be useful in that of table wine without SO2 addition. Orange juice was clarified by flotation using nitrogen or air as the foaming agent. Orange juice clarified by flotation using nitrogen as the foaming agent exhibited lower turbidity and a similar pulp content to that clarified by centrifugal separator (control). It had an acceptable taste and aroma. Juice clarified by flotation using air as the foaming agent, along with pectolytic enzyme treatment, exhibited much lower turbidity and pulp content compared to control. The clear juice had an acceptable taste but no aroma. The fermented clear juice was averagely rated, exhibiting a pleasant aroma and only a slightly bitter taste. The results indicate that flotation using nitrogen can be effective in the production of natural orange juice, while flotation using air may be useful in the production of orange drink. |
Optimal composition and heat processing requirements for canning of eggplant dip (Motabbal Al-bathinjan)Sharaf S. Omar, Ziad A. Abdullah, Mohammad A. Humeid, Mohammad I. YamaniCzech J. Food Sci., 2012, 30(1):35-44 | DOI: 10.17221/62/2010-CJFS Twenty formulas of eggplant dip, motabbal al-bathinjan in Arabic (MB), using different percentages of grilled eggplant, tahina (sesame pulp), and yogurt with constant levels of salt and citric acid were prepared and evaluated for the overall acceptability. The formula composed of 84.2% pulp of peeled grilled eggplant and 14% tahina without the addition of yogurt was found the most acceptable. The cold point of the canned MB was found to be in the geometric centre of the can. Canning of MB was conducted using three time/temperature combinations at the centre (80°C/5 min, 85°C/4 min, and 90°C/3 min). It was found that all heat-processes applied resulted in a commercially sterile canned MB with a high sensorial quality, as evidenced by the results of microbiological examinations, incubation tests, and sensory evaluation. Based on Bacillus coagulans, that may grow and cause flat sour spoilage of canned MB, the sterilisation value (F100) was estimated of the whole heat-process from the filling till cooling to about 70°C. |
Colour analysis and discrimination of laboratory prepared pasta by means of spectroscopic methodsMarie Hrušková, Ivan Švec, Hana SekerováCzech J. Food Sci., 2011, 29(4):346-323 | DOI: 10.17221/25/2011-CJFS For the CIE Lab colour profile determination of laboratory prepared pasta, two sample granulations and two spectral methods were tested. Pasta was manufactured progressively from semolina, common wheat, and corn flour. Sufficient colour spectra ranges were ensured by means of fortification with 9 non-traditional cereals in the first case, 8 natural colorants in the second one, and with 12 gluten-free pasta recipes in the last case. Both factors (i.e. granulation and spectral method) were proved as statistically significant by the cluster, variance and principal component analyses. In the comparison of the effects on the pasta composition and the spectral method, the latter demonstrated a stronger impact on the pasta colour profile measured. |
Risk analysis in drinking water accumulationJana Říhová Ambrožová, Jaroslav Říha, Jana Hubáčková, Iva ČihákováCzech J. Food Sci., 2010, 28(6):557-563 | DOI: 10.17221/98/2010-CJFS Drinking water is safe water, from the perspective of long-term use is does not cause any disease, pathogenic and hygienically unsafe microorganisms do not spread in it and customers enjoy its consumption. Drinking water is regarded as a foodstuff, therefore the known HACCP system can be used in the control system which can be applied not only directly to the final product, but also to the whole system of drinking water production, distribution, and accumulation. Even if there is no problem concerning the water processing and the technological line is well adjusted, the quality of drinking water is subsequently deteriorated by its transportation and accumulation. The condition and character of the operated distribution network and reservoirs are significantly and substantially related to the maintenance of the biological stability and quality of drinking water. This is well confirmed by biological audits of the distribution networks and water reservoirs. A significant fact is the negative influence of the secondary contamination by air in the reservoir facilities and the occurrence of microorganisms (fungi, bacteria) in free water and in biofilms. The findings obtained in the framework of biological audits were so alarming that the outputs of biological audits contributed to the reconsideration of the efficiency of the standard for the construction and design of water reservoirs and pointed out the necessity of its review. |
3-Chloropropane-1,2-diol fatty acid esters in potato productsVojtěch Ilko, Zuzana Zelinková, Marek Doležal, Jan VelíšekCzech J. Food Sci., 2011, 29(4):411-419 | DOI: 10.17221/468/2010-CJFS The levels of 3-chloropropane-1,2-diol (3-CPD) and fatty acid esters in raw potatoes, potato flakes, instant mashed potatoes, 2 potato dumplings, 32 French fries, and 61 potato crisps are reported. In a majority of the samples, free 3-CPD amount was under the limit of detection (< 3 μg/kg) or under the limit of quantification (< 9 μg/kg). Higher concentrations of free 3-CPD were found in potato flakes (37 μg/kg) and seven samples of potato crisps (10.4-46.2 µg/kg).Low concentrations of bound 3-CPD were present in raw potatoes (2 μg/kg), potato flakes (18 µg/kg), mashed potatoes (38 µg/kg) and potato dumplings (10-13 µg/kg). Higher levels of bound 3-CPD occurred in fried potato products. The amount of bound 3-CPD in pre-fried French fries was 27-64 µg/kg, in fried French fries its content was 100-258 µg/kg. In potato crisps, the bound 3-CPD amount was 98-2201 µg/kg. A striking difference was observed between the levels of bound 3-CPD in crisps fried in rapeseed oil and in fractionated palm oil (palmolein). For that reason, the changes were studied of the bound 3-CPD levels in palm oil after heating and in blends of rapeseed and palm oil during frying. It was proven that the frying oils absorbed into the fried potato products represent the main source of bound 3-CPD. |
β-glucans and their significance for the preparation of functional foods - a reviewMichaela Havrlentová, Zuzana Petruláková, Alena Burgárová, František Gago, Andrea Hlinková, Ernest ŠturdíkCzech J. Food Sci., 2011, 29(1):1-14 | DOI: 10.17221/162/2009-CJFS Cereals are generally known to have a positive influence on the general state of the human organism. The attention of the nutritional experts is paid especially to oats and barley. Besides their accessibility, these cereals are interesting due to their relatively high contents of soluble non-starch polysaccharides (fibrous material), out of which β-glucans have a dominant position from the aspect of health benefit. This paper presents a brief review of the latest knowledge on the positive effects of β-glucans on the consumer's health. The structure, occurrence, sources, and positive physiological effects of β-glucans on the cardiovascular system but also their antibacterial, antitumoral, immunomodulant, and radioprotective properties are mentioned. In the paper are given examples of β-glucans exploitation as functional ingredients in food, cosmetic, and pharmaceutical industries and as food additives on the basis of cereal fibres and cereal β-glucans. |
Design of a method to evaluate yeasts to be used as starter cultures in dry-cured meat productsEva M. Casado, Juan J. Córdoba, María J. Andrade, Mar RodríguezCzech J. Food Sci., 2011, 29(5):463-470 | DOI: 10.17221/41/2010-CJFS Some yeasts are involved in flavour development of dry-cured meat products showing a positive impact on the generation of volatile compounds. The aim of this work was to design a method of routine analysis to evaluate the production of volatile compounds by yeasts to be selected as starter cultures. For this purpose, several variations of a minimum culture medium that included free amino acids, oleic acid, and α-ketoglutarate, incubated under similar conditions of water activity and pH as dry-cured meat products, were assayed. In these conditions, the representative yeast strains isolated from a dry-cured meat product were tested. The volatile compounds were analysed using Solid Phase Micro-Extraction and gas chromatography/mass spectrometry. In the designed media, the tested yeasts produced volatile compounds involved in flavour development of dry-cured meat products. In addition, all the strains showed the highest production of these volatile compounds in the complete minimum culture medium witch included α-ketoglutarate and oleic acid. |
Antioxidant capacity and antioxidants of strawberry, blackberry, and raspberry leavesLucie Buřičová, Mirjana Andjelkovic, Anna Čermáková, Zuzana Réblová, Ondřej Jurček, Erkki Kolehmainen, Roland Verhé, František Kvasnička6Czech J. Food Sci., 2011, 29(2):181-189 | DOI: 10.17221/300/2010-CJFS The total phenolic content (Folin-Ciocalteu method), free radical scavenging ability expressed as DPPH value, ferric reducing antioxidant capacity (FRAP), and oxygen radical absorbance capacity (ORAC) were determined in water extracts of leaves from Rosaceae family plants (Fragaria vesca L., Rubus fructicosus L., and Rubus idaeus L.). The antioxidant capacities of the extracts (in the order of the above mentioned methods) were 73.6-88.9%, 60.1-71.4%, 49.7-78.0% respectively, and 45.3-66.5% of that of green tea water extract. Further, the presence of 15 compounds (gallic acid, rutin, ellagic acid, caffeic acid, p-coumaric acid, quercetin, kaempferol, myricetin, quercetin-3-d-glucoside, ascorbic acid, (+)-catechin, (-)-epicatechin, epicatechingallate, epigallocatechin, procyanidin B1) was studied by HPLC-ECD and their antioxidant capacities were compared to the antioxidant capacity of the extracts. Out of the compounds studied, mostly (+)-catechin, ellagic acid, and (-)-epicatechin participated in the antioxidant capacities of the studied plant leaves water extracts. The antioxidant capacity of leaves infusions (determined by DPPH method) was lower than those of red wines and tea infusions, but comparable to the antioxidant capacities of white wines and fruit beverages. |
Antioxidant and antimicrobial activities of beet root pomace extractsJasna M. Čanadanović-Brunet, Sladjana S. Savatović, Gordana S. Ćetković, Jelena J. Vulić, Sonja M. Djilas, Siniša L. Markov, Dragoljub D. CvetkovićCzech 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 power of all the beet root pomace extracts increased with increasing concentrations. The DPPH-free radical scavenging activity of the extracts, expressed as EC50, ranged from 0.133 mg/ml to 0.275 mg/ml. Significant correlation was observed between all phytochemical components and scavenging activity. 0.5 mg/ml of ethanol extract completely eliminated hydroxyl radical, which had been generated in Fenton system, while the same concentration of this extract scavenged 75% of superoxide anion radicals. In antibacterial tests, Staphylococcus aureus and Bacillus cereus showed higher susceptibility than Escherichia coli and Pseudomonas aeruginosa. |
Yeast assimilable nitrogen in South Moravian grape musts and its effect on acetic acid production during fermentationMojmír BaroňCzech 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 production of acetic acid was low (215.8 mg/l); this indicated that in the majority of must samples without added nutrients, the course of fermentation was smooth and trouble-free. The results obtained confirm that the method of formaldehyde titration is universal and simple, thus it can be recommended for winemakers as a useful and efficient analytical tool. |
A Comparative Study of the Analysis of Free Fatty Acids in Cheeses (Cow's, Ewe's and Goat's) with Different Ripening Times using NIRS: Intact Samples and Fat ExtractsI. González-Martín, J. M Hernández-Hierro, I. Revilla, A. Vivar-Quintana, R. Morón-Sancho, J. Salvador-EstebanCzech J. Food Sci., 2009, 27(10):S105 | DOI: 10.17221/964-CJFS Lipolysis is of great importance in the development of the aroma and flavour of cheese and one of the usual ways of measuring it is to assess variations in fatty acids. The relative proportions of fatty acids in milk fat depend on the animal species, the stage of lactation and feed regime, the ripening time and the climatic conditions and microbiological quality of the milk. GC-MS is the reference method for the determination of fatty acids in cheeses, but the technique involves long analysis times. |
Discriminatory power assessment of the sensor array of an electronic nose system for the detection of non alcoholic beer agingMahdi GHASEMI-VARNAMKHASTI, Seyed Saeid MOHTASEBI, Maryam SIADAT, Seyed Hadi RAZAVI, Hojat AHMADI, Amadou DICKOCzech J. Food Sci., 2012, 30(3):236-240 | DOI: 10.17221/165/2011-CJFS Many chemical changes in beer aroma occur during storage (aging), and monitoring these changes could give guidelines to the brewers how to manage and control the brewing process to obtain the final product with a high stability in flavour after packaging. In this regard, our laboratory aimed at a research into the application of an electronic nose in order to get the fingerprint of the change of non alcoholic beer aroma during aging. Th discriminatory power of the sensor array of this system was evaluated. Principal Component Analysis (PCA) and Soft Independent Modelling of Class Analogy (SIMCA) techniques were used for this purpose. The results obtained can direct us to performing other parts of our project. Considering the discriminatory power of the sensor array used, we can develop the application of a specific electronic nose system by picking up the most effective sensors or ignoring the redundant sensors. |
Application of ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) metabolomic fingerprinting to characterise GM and conventional maize varietiesOriginal PaperLukáš VÁCLAVÍK, Jaroslava OVESNÁ, Ladislav KUČERA, Jan HODEK, Kateřina DEMNEROVÁ, Jana HAJŠLOVÁCzech J. Food Sci., 2013, 31(4):368-375 | DOI: 10.17221/177/2013-CJFS The feasibility of metabolomic fingerprinting approach based on ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOFMS) was studied to assess its ability to discriminate between maize varieties, and to show the associations between them on the metabolomic level. The non-targeted metabolomic analysis was applied to assess the variability within two varieties grown under different environmental conditions and to characterise the association within a sample set comprising both conventional and transgenic (MON-ØØ81Ø-6) maize varieties cultivated under the same environmental conditions (locality). Typical metabolomic fingerprints were established for individual plants. The plants representing two varieties formed well separated clusters. Metabolomic fingerprints of the second sample set enabled their unambiguous discrimination. The differences in metabolomic fingerprints between maize varieties were identified and documented by grouping in PCA and/or CA. The results indicate a similar genetic basis of transgenic maize varieties as they descend from a MON 810 event. The results explicitly showed that the variability of the metabolites in MON 810 did not exceed the ranges measured within the conventional varieties, thus supporting the concept of substantial equivalence. |
Determination of water-insoluble β-D-glucan in the whole-grain cereals and pseudocerealsBernadetta Hozová, Ľudovít Kuniak, Petra Moravčíková, Alena GajdošováCzech J. Food Sci., 2007, 25(6):316-324 | DOI: 10.17221/747-CJFS Water-insoluble β-(1,3)-D-glucan (lichenan) was determined in 43 samples of various cereal (oats, barley, wheat, millet) and pseudocereal (buckwheat, amaranth) cultivars using a modified procedure with fungal α-amylase (Fermizyme P 300). The content of water-insoluble β-glucan varied in the dependence on the cereal species and cultivars. The highest content was registered in covered oat cultivars (Cyril and the new breeding cultivar PS-100) ranging from 26.7 to 28.2 g/100 g dry matter (d.m.) followed by less traditional cereals such as millet (Panicum miliaceum L.), amaranth (Amaranthus sp. L.), and buckwheat (Fagopyrum) - more than 20 g/100 g d.m. A somewhat lower average content of water-insoluble β-glucan was found in wheat - 12.7-16.2 g/100 g d.m., in spelt wheat - 8.5 g/100 g d.m., and in oats - varying between 15.3 and 18.7 g/100 g d.m. |
Mycotoxin production, chemotypes and diversity of Czech Fusarium graminearum isolates on wheatOriginal PaperTaťána Sumíková, Ludmila Gabrielová, Ladislav Kučera, Martin Žabka, Jana ChrpováCzech J. Food Sci., 2013, 31(4):407-412 | DOI: 10.17221/286/2012-CJFS Fusarium head blight (FHB) is a serious cereal disease in the CzechRepublic. The most important pathogen associated with FBH is Fusarium graminearum, which can produce trichothecenes, mainly deoxynivalenol (DON) and its derivates. A set of 103 F. graminearum isolates were isolated from naturally infected wheat ears collected from 20 localities (25 ears from one locality) within the Czech Republic, in the year 2004. The ears were evaluated for DON content by ELISA. Maximum detected value was 30.7 mg/kg. A group of PCR assays targeting the segments of the Tri7, Tri13 and Tri3 genes were used to determine the chemotypes of F. graminearum isolates. All the isolates belonged to DON producing chemotype. Further discrimination revealed that almost all (99.03%) isolates belonged to 15-ADON chemotype, and only one (0.97%) isolate belonged to 3-ADON chemotype. The genetic variability of the isolates was assessed from their AFLP fingerprints. The populations were highly heterogeneous both within and between locations, and no clear evidence for the association between AFLP profile and geographic origin was found out. |
Prevalence, distribution, and antimicrobial susceptibility of Staphylococcus aureus in ready-to-eat salads and in the environment of a salad manufacturing plant in Northern GreeceDaniel Sergelidis, Amin Abrahim, Vasiliki Anagnostou, Alexandros Govaris, Theofilos Papadopoulos, Anna PapaCzech J. Food Sci., 2012, 30(3):285-291 | DOI: 10.17221/37/2011-CJFS The prevalence, distribution, and antibiotic susceptibility of Staphylococcus aureus was investigated in ready-to-eat (RTE) salads, the environment, and the personnel of a salad producing plant in Greece. Staphylococci were isolated from 27% of the samples. Apart from three isolates which were sensitive to all antibiotics, all the others exhibited resistance from two up to five antibiotics. None of the isolates was resistant to oxacillin. Random Amplified Polymorphic DNA (RAPD) analysis showed no genetic relation between the human and salad isolates while one RAPD clone of S. aureus predominated among the salad samples. The results suggest that an effective application of Good Manufacturing Practices (GMP) is needed along the food production chain to prevent the contamination of RTE foods. |
Outdoor environment as a source of Listeria monocytogenes in food chainTereza Gelbíčová, Renáta KarpíškováCzech J. Food Sci., 2012, 30(1):83-88 | DOI: 10.17221/7/2011-CJFS We monitored the presence of Listeria monocytogenes in environmental sources and to evaluate the phenotypic and molecular characteristics of the isolates recovered. L. monocytogenes was isolated in 12 (11.2%) of the 107 samples from the wild, farm environment, and vegetation. Most isolates (83.3%) were of serotype 1/2a and the remainder (2) were of serotype 4b. All 12 isolates were susceptible to the whole range of antimicrobials tested. These12 strains were carriers of the virulence genes prfA, hlyA, actA, plcA, plcB, inlA, inlB, inlC, and inlJ. The detection of the inlA gene in 4 (33.3%) of 12 strains using the PCR-RFLP suggests the potential of some of these strains to penetrate into epithelial cells of the intestinal barrier. Macrorestriction analysis also confirmed clonal identity of some environmental isolates with food and human isolates. These results indicate that the external environment is a source of potentially pathogenic strains of L. monocytogenes. |
Detection of genetically modified soya, maize, and rice in vegetarian and healthy food products in SerbiaOriginal PaperGordana Zdjelar, Zorica Nikolić, Ivana Vasiljević, Biljana Bajić, Dušica Jovičić, Maja Ignjatov, Dragana MiloševićCzech 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 that the investigated samples were imported mainly from EU countries, it can be concluded that the control of GMOs is carried out systematically and in accordance with the Serbian GMO Law. |
Differences in the amino acid composition of the breast muscle of wild and farmed pheasantsAdam Brudnicki, Anna Kułakowska, Dominika Pietruszyńska, Małgorzata Łożyca-Kapłon, Jan WachCzech J. Food Sci., 2012, 30(4):309-313 | DOI: 10.17221/17/2011-CJFS Numerous studies show the slaughter yield and also basic chemical composition of pheasant meat. The results reveal a higher biological value of the meat of pheasants which were fed naturally, in comparison to the meat of pheasants fed with commercial mixtures. In many countries, the pheasant is selected with the aim of producing high quality meat with very desirable nutritional values. There are only few publications on amino acid composition of pheasant meat. The knowledge of amino acid composition of pheasant meat can be used to determine its potential nutritional value. The amino acid compositions were compared of the meats of wild and farm pheasants. In the study, the following amino acids were determined: Asp, Thr, Ser, Glu, Pro, Gly, Ala, Val, Ile, Leu, Tyr, Phe, His, Lys, Arg. An improved amino acid profile was found in the breast muscle of pheasants kept at the farm in comparison with that of wild pheasants. |
Reliability of PCR based screening for identification and quantification of GMOsJaroslava Ovesná, Ladislav Kučera, Jan Hodek, Kateřina DemnerováCzech J. Food Sci., 2010, 28(2):133-138 | DOI: 10.17221/67/2009-CJFS Handling with genetically modified organisms (GMOs) is regulated namely in EC. Laboratories often use polymerase chain reaction (PCR) based screening methods to monitor the presence of GM particles in food commodities as a cost effective approach. The reliability was tested of such screening using 35S CaMV promoter as the target sequences. Soya grown from non-GM cultivar as declared by a seed company was investigated after the harvest, transport to the silo, and before processing. The results based on PCR and real-time PCR analysis clearly showed that, the contamination with debris of other species, dust during transport, storage, and other kind of handling led to contamination with detectable amounts of Cauliflower mosaic virus (CaMV). Impurities are allowed by EC regulations but may, as we have shown, interfere with the analytical procedures based on PCR. The identification of 35S CaMV promoter and NOS terminator in food with uncertain history and no approved specific events may indicate unknown GMOs and perhaps emergency situation. |
Changes in quality parameters of vodka filtered through activated charcoalLucie Siříšťová, Šárka Přinosilová, Kateřina Riddellová, Jana Hajšlová, Karel MelzochCzech J. Food Sci., 2012, 30(5):474-482 | DOI: 10.17221/361/2011-CJFS The production technology of high-quality vodka used in Russia involves filtration through activated charcoal. To approach the quality of renowned Russian vodka, one prominent Czech spirit-producing company installed on its production premises a filtration device including a charcoal column, and launched test runs during which different filtration conditions were tested. Samples collected during the test runs were analysed by GC-FID and GC-MS with the aim to compare their composition; sensory analysis was an integral part of the evaluation. The results documented a positive effect of charcoal filtration on the quality of produced vodka, which was not reduced when higher flow rates were applied. |
Funcionality of several cake ingredients: A comprehensive approachOriginal PaperJulia Rodríguez-García, Ana Puig, Ana Salvador, Isabel HernandoCzech J. Food Sci., 2013, 31(4):355-360 | DOI: 10.17221/412/2012-CJFS The roles of some cake ingredients - oil, a leavening agent, and inulin - in the structure and physicochemical properties of batter and cakes were studied in four different formulations. Oil played an important role in the batter stability, due to its contribution to increasing batter viscosity and occluding air during mixing. The addition of the leavening agent was crucial to the final height and sponginess of the cakes. When inulin was used as a fat replacer, the absence of oil caused a decrease in the stability of the batter, where larger air bubbles were occluded. Inulin dispersed uniformly in the batter could create a competition for water with the flour components: gluten was not properly hydrated and some starch granules were not fully incorporated into the matrix. Thus, the development of a continuous network was disrupted and the cake was shorter and softer; it contained interconnected air cells in the crumb, and was easily crumbled. The structure studies were decisive to understand the physicochemical properties. |
Analysis of the lipid fractions of coffee creamers, cream aerosols, and bouillon cubes for their health risk associated constituentsLenka Karšulínová, Blanka Folprechtová, Marek Doležal, Jana Dostálová, Jan VelíšekCzech J. Food Sci., 2007, 25(5):257-264 | DOI: 10.17221/679-CJFS Fifteen coffee creamers, 10 cream aerosols, and 5 bouillon cubes from the retail market were analysed, principally for their contents of trans-fatty acids that are known to increase the risk of coronary heart disease, and for their contents of 3-chloropropane-1,2-diol (3-MCPD) fatty acid esters that possibly have a bioaccumulation potential. The contents of trans-fatty acids in coffee creamers, cream aerosols and bouillon cubes were in the range of 0.2-32.8%, < LOD - 6.0%, and 0.5-2.1% of total fatty acids, respectively. All samples contained high levels of 3-MCPD fatty acid esters that were determined after releasing the free 3-MCPD by methanolysis. The 3-MCPD levels in coffee creamers, cream aerosols, and bouillon cubes were in the range of 130-730 µg/kg (540-4480 µg/kg fat), 50-730 µg/kg (220-2880 µg/kg fat), and 380-670 µg/kg (2650-4840 µg/kg fat), respectively. The results showed that the refined and hydrogenated oils may represent a certain risk. The highest levels of 3-MCPD esters were found in a sample of refined palm oil (4170 µg/kg). Currently, there is no information available on how these 3-MCPD esters are metabolised, to which extent they are hydrolysed or biosynthesised in the body, to which extent they are deposited in tissues, and how they influence the properties and functions of tissues (if they really do it). |
