Czech Journal of Food Sciences, 2012 (vol. 30), issue 1
Vibration assisted cutting of Gouda cheese
Andrej Lebar, Oki Blatnik, Mihael Junkar, Henri Orbanić
Czech J. Food Sci., 2012, 30(1):1-8 | DOI: 10.17221/190/2009-CJFS 
The influence of vibrations on the process of cheese cutting applied in order to reduce friction and the cutting force was studied. The forces needed to cut through the cheese samples were measured against the variations of the temperature, cutting speed, and vibration frequency. The hypothesis which induced the research work was that assisting vibrations reduce the cutting forces and make the cutting easier for the user. In the experiments,Goudacheese was used at 10°C and 22°C. The further, a conventional kitchen knife was used with four different cutting speeds from 12.5 mm/s to 75 mm/s and six vibration frequencies from 0 Hz to 150 Hz. The results...
Fermentation of native wheat, potato, and pea starches, and their preparations by bifidobacterium - changes in resistant starch content
Małgorzata Wronkowska, Maria Soral-Śmietana
Czech J. Food Sci., 2012, 30(1):9-14 | DOI: 10.17221/18/2011-CJFS
The capability was studied of the selected Bifidobacterium strains to utilise the resistant starch fraction (RS) from native starches of the following origin: wheat, potato, and pea, and their preparations obtained experimentally by physical and enzymatical modifications. Furthermore, the potential influence of the gelatinisation process on the degree of utilisation of RS from the investigated starch samples was studied. The following strains: B. pseudolongum KSI9, B. animalis KS20a1, and B. breve KN14, were chosen. The native starches and their preparations were characterised by their different contents of the RS...
Cyclodextrin production from amaranth starch by cyclodextrin glycosyltransferase produced by Paenibacillus macerans CCM 2012
Marian Urban, Miloš Beran, Lubomír Adámek, Josef Drahorád, Petr Molík, Kristina Matušová
Czech J. Food Sci., 2012, 30(1):15-20 | DOI: 10.17221/226/2010-CJFS
Cyclodextrins (CDs) are synthesised by bacterial extracellular enzym cyclodextrin glycosyltransferase (CGTase, E.C. 2.4.1.19) from starch or starch derivatives. The production of α-, β-, and γ-CDs by CGTase from Paenibacillus mace-rans CCM 2012 was studied in regard to the effect of the starch source (amaranth, maize) on the yield of CDs. CGTase was produced by a 3-day sterile cultivation in the laboratory Bench-top fermentor BiostatB under aerobic conditions. CGTase was partially purified by ammonium sulfate precipitation at 60% saturation. Electrophoretic analysis (SDS-PAGE) of the isolated CGTase enzyme was carried out...
Diastase number changes during thermaland microwave processing of honey
Stanisław Kowalski, Marcin Lukasiewicz, Szczepan Bednarz, Marzena Panuś
Czech J. Food Sci., 2012, 30(1):21-26 | DOI: 10.17221/123/2010-CJFS
The presented paper covers the preliminary studies on microwave inactivation of honey enzymes described as diastase number (DN). All the investigations were done on commercially available honey from Polish local market. Microwave processes were compared to the conventional ones. In the case of conventional conditions, the constant rate of diastase enzyme inactivation was estimated using the first order kinetics. In the case of microwave heated samples, it was impossible to establish the rate constant; however, the investigation proved the suitability of such kind of processing for short-term thermal treatment of honey.
Brewing trials with spring and winter barley varieties
Alexandr Mikyška, Vratislav Psota, Miloš Hrabák
Czech J. Food Sci., 2012, 30(1):27-34 | DOI: 10.17221/145/2010-CJFS
The effects of a set of barley varieties on the brewing process and quality of beer production intermediaries were studied in trial brews (40 l) prepared using the two-mash decoction process. The varieties included in the trial were selected based on the starch granule size distribution determined previously. A significant effect of the varieties on the saccharification time of both mashes was determined. The highest saccharification rate in brews was achieved with the variety Jersey; the saccharification time of the 1st and 2nd mash with the variety Tiffany was markedly longer. The varieties with a greater fraction of large starch...
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. Yamani
Czech 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...
Preparation of flaxseed for lignan determination by gas chromatography-mass spectrometry method
Hrvoje Sarajlija, Nikolina Čukelj, Dubravka Novotni, Gordan Mršić, Mladen Brnčić, Duška Ćurić
Czech J. Food Sci., 2012, 30(1):45-52 | DOI: 10.17221/107/2010-CJFS
Since 1980s, several methods for the determination of lignans in food samples have been developed depending on the types of lignans and foods analysed, but mostly on flaxseed as a reference food. In this work, specific steps in flaxseed preparation for lignan secoisolariciresinol analysis by gas chromatography-mass spectrometry method were examined. Ethanol extraction of lignan from defatted and non-defatted flaxseed before acid hydrolysis yielded significantly lower concentrations (5172 ± 49 μg/g; 5159 ± 83 μg/g, respectively), when compared to the direct acid hydrolysis (8566 ± 169 μg/g; 8571 ± 192 μg/g, respectively)....
Formation of acrylamide during baking of shortcrust cookies derived from various flours
Karolina Miśkiewicz, Ewa Nebesny, Joanna Oracz
Czech J. Food Sci., 2012, 30(1):53-56 | DOI: 10.17221/287/2010-CJFS
Asparagine and reducing sugars are the principal acrylamide precursors in foods. Their main sources in pastries are flour and hen egg yolks. The concentrations of asparagine and carbohydrates vary with flour and depend on multiple factors like environmental conditions during the cultivation of cereals and post-harvest processing methods. An objective of this study was finding the interplay between amino acid and carbohydrate profiles of the selected flours and their blends and acrylamide concentrations in the cookies derived from them. Shortcrust cookies were prepared from five different flours such as wheat Poznańflour and flours from spelt-wheat,...
Methodology development for routine estimation of chlorpropham in commercial potato stores
Waqar A. Khan, H.J. Duncan, Ahmad K. Baloch, Geraldine McGowan
Czech J. Food Sci., 2012, 30(1):67-73 | DOI: 10.17221/329/2010-CJFS
Chlorpropham is employed worldwide as an anti-sprout chemical to the harvested potato tubers during storage. A simple and precise analytical technique is developed for routine estimation of the sprout suppressant from a large number of potato samples supplied from commercial stores demanding quick analysis. Chlorpropham is extracted completely from potato tubers by intelligent reflux extraction followed by quantification using GC-FID (Gas Chromatography-Flame Ionization Detector) equipment. In this article, the performance of the technique is compared with the lengthy extraction/cleanup process, and the results are validated as per one-way analysis...
Simultaneous determination of the residues of fourteen quinolones and fluoroquinolones in fish samples using liquid chromatography with photometric and fluorescence detection
Florentina Cañada-Cañada, Anunciacion Espinosa-Mansilla, Ana Jiménez Girón, Arsenio Muñoz de la Peña
Czech J. Food Sci., 2012, 30(1):74-82 | DOI: 10.17221/12/2010-CJFS
A chromatographic method is described for assaying fourteen quinolones and fluoroquinolones (pipemidic acid, marbofloxacin, norfloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid, flumequine, and pyromidic acid) in fish samples. The samples were extracted with m-phosphoric acid/acetonitrile mixture (75:25, v/v), purified, and preconcentrated on ENV + Isolute cartridges. The determination was achieved by liquid chromatography using C18 analytical column. A mobile phase composed of mixtures of methanol-acetonitrile-10mM citrate buffer at pH 4.5, delivered under...
Outdoor environment as a source of Listeria monocytogenes in food chain
Tereza Gelbíčová, Renáta Karpíšková
Czech 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...
Characterisation of antilisterial bacteriocin-like substance produced by Enterococcus mundtii
Kateřina Solichová, Ivana Složilová, Iva Jebavá, Barbora Uhrová, Milada Plocková
Czech J. Food Sci., 2012, 30(1):89-97 | DOI: 10.17221/278/2010-CJFS
The antilisterial activity of E. mundtii 1282 strain and its cell-free neutralised supernatant was observed against five persistent L. monocytogenes strains using the agar spot method. The enterococcal metabolite was consequently characterised as a proteinaceous substance - the bacteriocin-like substance, which was heat-stable at heating to 100°C for 30 min, stable at pH 2-12, and still active after eight-week long storage at 6°C and -20°C. The bacteriocin-like substance reached the highest activity of 6400 AU/ml after ten hours of cultivation of E. mundtii 1282 strain, when it was at the stationary phase of its growth. E....