Authors:M. Karwowski, M. Masson, M. Lenzi, A. Scheer and C. Haminiuk
This study assessed the rheological behaviour, physical stability, and the phenolic compounds of Eugenia pyriformis Cambess. (uvaia) and Eugenia uniflora L. (pitanga) fruits. The effect of temperature on the rheological behaviour of the fruit was evaluated (10–60 °C) by means of non-oscillatory rheological analysis in a rheometer. The whole samples (purée) exhibited shear-thinning behaviour (n<1), whereas the centrifuged samples exhibited Newtonian behaviour (n=1). The Arrhenius equation accurately described the effect of temperature on the apparent viscosity of the fruit. The stability study was performed by means of sedimentation and turbidity testing. The stabilisation of purées occurred on the second (Eugenia pyriformis Cambess.) and on the third (Eugenia uniflora L.) day of storage. The results demonstrated that turbidity increased with an increase in homogenization velocity. The phenolic compounds of the fruit were identified and quantified by reverse-phase high-performance liquid chromatography (RP-HPLC). The samples presented significant differences in the concentration of phenolic compounds. Among the phenolic acids identified, gallic acid was the one with higher concentration in both fruit assayed. Comparing the fruits, it was observed that Eugenia pyriformis presented higher content of flavonoids (5-fold) and Eugenia uniflora presented higher content of phenolic acids (8.5-fold), especially gallic acid. Myricetin and quercetin were the main flavonoids determined in Eugenia pyriformis.
Authors:M. Abu-Darwish, M. Gonçalves, C. Cabral, C. Cavaleiro and L. Salgueiro
Juniperus phoenicea L. (Cupressaceae) is an evergreen small tree or shrub, distributed throughout the Mediterranean area from Portugal to Israel and North Africa. J. phoenicea has been used for centuries in traditional medicine and its berries are widely used in flavours, perfumes, and to aromatize alcoholic beverages.The aim of the present work was to evaluate the chemical composition and antifungal activity of essential oils of Juniperus phoenicea berries from Jordan.The essential oils of the berries were isolated by hydrodistillation and analysed by GC and GC-MS. Minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the essential oils against dermatophytes, yeasts and Aspergillus species.The essential oils were characterized by high percentage of α-pinene (75.5 and 84.2%), which distinguish them from oils from other countries where α-pinene is usually present in lower percentages. Essential oils exhibited high antifungal activity against dermatophytes and Cryptococcus neoformans with MIC values ranging from 0.32–2.5 μl ml−1.These results support that essential oils from J. phoenicea berries may be useful in the treatment of dermatophytosis. Further studies should be stimulated in order to evaluate toxicity and optimal concentrations for clinical applications.
The characterization of four types of Indian honeys (Trifolium alexandrinum (berseem clover), Brassica sp. (mustard), Helianthus annuus (sunflower), Eucalyptus lanceolatus) was carried out on the basis of their quality parameters (moisture, pH, free acidity, reducing sugars, sucrose, fructose/glucose ratio, colour, ash content, proline content, invertase activity, diastase activity, hydroxymethylfurfural (HMF), and mineral content (sodium, potassium, iron, calcium, zinc, and copper). The source of honey had a significant (P<0.05) effect on moisture content, free acidity, pH, reducing sugar content, fructose/glucose ratio, hydroxymethylfurfural content, invertase and diastase activities, sucrose content, proline, ash content, and mineral content. Pattern recognition methods, such as principal component analysis and linear discriminate analysis, were performed to classify honey on the basis of physicochemical properties and mineral content. The variables calcium, pH, and potassium exhibited higher discrimination power.
The aim of this study was to develop an accurate, fast and safe routine diagnostic method based on protein studies for differentiating between T. caries and T. controversa at species level. Since import of wheat contaminated with T. controversa is restricted by several countries, differentiation of T. controversa from the more prevalent T. caries is of economic interest. The newly developed method is based on distilled water washing followed by the rupturing of the teliospore walls in PBS extraction medium, and an SDS electrophoresis (10% resolving gel). The electrophoretic pattern showed consistent species-related differences in a 106 kDa polypeptide that appeared in each extract of T. controversa, but was not present in the protein extracts of T. caries. The newly developed method could be of value for the authorities performing routine monitoring of T. controversa as an up-to-date diagnostic assay in wheat shipments.
In this study, detection of an obligate aerobic, thermophilic and acidophilic bacterium, the sporeforming Alicyclobacillus acidoterrestris was performed by determination of its specifc metabolite, guaiacol. Since its spores have been shown to resist conventional pasteurization, it has become a potential spoilage concern for fruit and vegetable juices, mainly for apple and orange juices. Detection of guaiacol was carried out by using an NST 3320 type electronic nose, and other methods, such as peroxidase-based enzymatic method with UV-Vis spectrophotometer, SPME-GC-MS technique and an untrained sensory panel were also applied. The results indicated that based on their detection limit the methods can be ordered in the following way: SPME-GC-MS (detection limit: <0.5 ppm)<sensory evaluation (detection limit: 0.5–1 ppm)<spectrophotometric method=electronic nose technique (detection limit: 1.25–2.5 ppm).
Authors:S. Emen Tanrikut, B. Çeken, S. Altaş, M. Pirinççioğlu, G. Kizil and M. Kizil
Rheum ribes L. (Polygonaceae) is a common species of rhubarb in Turkey, which is also found in Iraq, Iran, Pakistan, Afghanistan, and Russia. The antioxidant potency of stems was investigated employing various in vitro systems, such as lipid peroxidation in rat brain homogenate, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radical scavenging, ferric reducing power, metal chelation activity. R. ribes stem parts showed strong inhibitory activity toward lipid peroxidation of rat brain homogenate induced by the FeCl3-ascorbic acid system. R. ribes extract was able to reduce the stable free radical DPPH 83.9±1.90% at 150 μg ml−1. The reducing power of the extract was 0.46±0.074 at 250 μg ml−1. The effect of extract of R. ribes on DNA cleavage induced by UV-photolysis of H2O2 using pBluescript M13+ plasmid DNA was also investigated. This extract significantly inhibited DNA damage induced by reactive oxygen species (ROS). These findings demonstrate that aqueous extract from fresh stems of R. ribes has antioxidant activity and thus have great potential as a source for natural health products.
Authors:Á. Vajda, I. Zeke, R. Juhász, J. Barta and Cs. Balla
The aim of the present study was to examine the infuence of hydrolyzed, nanofltered concentrate of the ultrafltered permeate (HNF concentrate) of acid whey on the quality characteristics of milk-based ice cream. Thermophysical properties were determined by differential scanning calorimeter, consistency was measured by oscillatory rheometer, and sensorial quality was evaluated by scoring method. It was concluded that the acid whey did not increase the melting of the product, and reduced the freezing point. Cryoscopic temperature, onset point, and glass transition temperature (Tg) gradually decreased as the quantity and proportion of acid whey increased in the ice-cream. Rheological results indicated that using HNF, acid whey produced more creamy and smooth ice-cream. However, because of its characteristic taste, maximum 20% of milk could be replaced by HNF acid whey in milk-based ice-creams.
Eight Lactobacillus, five Saccharomyces and one Streptococcus strains were chosen to perform mono and mixed culture fermentations, focusing on interaction investigation via agar diffusion and analysis of cell growth kinetics, both serving as selection criteria. Mixed culture fermentations with four lactic acid bacteria (Lb. bulgaricus, Lb. paracasei SF1, Lb. plantarum 2142, and Lb. casei Shirota) and four yeast strains (S. cerevisiae W66, S. cerevisiae WS34/70, S. cerevisiae W120, and S. carlsbergensis 843) were performed in wort with initial cell ratio of 1:1. It was determined that during fermentations, cell concentration of lactic acid bacteria exceeded that of yeasts by one order of magnitude. Three strain combinations (S. carlsbergensis with Lb. bulgaricus, Lb. 2142, and Lb. Shirota) were chosen for further fermentations. Basic behaviour of them in wort was studied in mono culture, which helped to determine interaction type between bacteria and yeast in mixed culture. It resulted in higher Lactobacillus cell concentration in mono cultural than in mixed culture fermentation, which refers to competition. Cell ratio was changed to 1:10 (lactobacilli:yeasts), to favour growth of yeast and avoid lower pH. Despite the higher initial concentration of yeast, results turned in favour of lactobacillus already at the 24th hour.
Authors:D. Nagy, M. Krassóy, I. Zeke, K. Pásztor-Huszár and Cs. Balla
The aim of the study was to select the most suitable freezing and thawing method for preserving the quality of pasta flata type Parenica cheese comparing different methods: slow, shock (circulated air) and cryogenic freezing and thawing at room temperature and in a refrigerator, respectively. To observe the effects of these methods on some cheese properties weight, pH, and dry-matter content were measured, stringiness was examined, and compression test were performed for texture analysis. Thermophysical properties were determined by DSC: unfreezable water content, onset point of melting, and latent heat. Sensory analyses were also carried out by profle analysis. Results of objective and subjective measurements showed similar trends: characteristics of cheese samples frozen in circulated air and thawed in refrigerator resembled the most to the control sample.
Authors:O. Csernus, I. Bata-Vidács, J. Farkas and J. Beczner
The effect of water activity (0.85–0.99 aw) and temperature (20–35 °C) on growth of two potentially toxigenic moulds, Aspergillus niger and Penicillium expansum, were studied. On the basis of the measured colony diameter ComBase DMFit program was used to estimate the lag phase and growth rate. Similar results may provide basis for the risk assessment of fungal growth (and also for the possible mycotoxin contamination) in food and feed plants in the vegetation season due to the climate change (global warming), and also during unfavourable storage conditions.
Authors:G. Jurak, J. Bošnir, D. Puntarić, I. Pavlinić-Prokurica, Z. Šmit, H. Medić, I. Puntarić and E. Puntarić
The aim of the study was to determine the possible presence of N-nitrosamines in liver pâtés available on the Croatian market and to compare them with a liver pâté from the EU market. In addition, the effects of temperature and length of storage on N-nitrosamine concentrations were assessed. A total of 630 samples were randomly chosen. Thirty samples of each were analysed immediately upon sampling, whereas another 30 samples were stored for 5 and 10 days at 4 °C, 22 °C and 37 °C, respectively. In the samples stored at 4 °C, the mean total N-nitrosamine level was 1.3–6.8 μg kg−1 on day 5 and 1.0–5.0 μg kg−1 on day 10. In the samples stored at 22 °C, the mean total N-nitrosamine level was 3.6–9.3 μg kg−1 (day 0), 11.9–24.5 μg kg−1 on day 5, and 22.7–32.3 μg kg−1 on day 10. In the samples stored at 37 °C, the mean total N-nitrosamine level was 104.9–231.1 μg kg−1 (day 5) and 801.3–1329.0 μg kg−1 (day 10). Temperature and length of storage were found to be associated with the formation of N-nitrosamines in meat products, but carcinogenic N-diethylnitrosamine (diEt) in particular, accidentally or not, was not present at all in the products originating from the EU.
Authors:I. Rumora, I. Kobrehel Pintarić, J. Gajdoš Kljusurić, O. Marić and D. Karlović
This study elucidates the key success of using statistical modelling in the design and development of a new product (milk toffee) as potential new functional food product. The standard milk toffee recipe was modified in order to produce new products with less sugar, more inulin, and decreased energy content. From the consumers point of view, a product has to be healthy (acceptable ingredients like low sugar content or inclusion of inulin) and tasty (good sensory properties). This is an opportunity to use chemometric strategies that can highlight information in relation to different ingredients and preferable taste attributes. Multivariate exploratory techniques were used in order to detect relationship between the milk toffee ingredients (sugar, water, condensed milk, glucose syrup, fat, salt, sorbitol, and emulsifier E 471) and sensory attributes of taste and texture (sweetness and hardness) chosen for this research.Results showed that the sweetness is a direct outcome of added sugar, glucose syrup, and condensed milk, and the hardness, as the next important sensory attribute of a milk toffee, is positively correlated with the content of fat, glucose syrup, water, salt, and E 471. Statistical modelling proved to be a useful tool for elucidating the relationship between ingredients and sensory properties of the milk toffee and can be a useful tool in the complex interpretations of changes in product design and development.
Authors:D. Varga, Cs. Hancz, P. Horn, T. Molnár and A. Szabó
Four important Hungarian common carp (Cyprinus carpio L.) breeds (Attala mirror, Attala scaled, Hortobágy scaled and Szeged mirror) harvested from different fish farms were analysed in this study. Main body indices, slaughter characteristics, fillet fat content, and conventional fish flesh quality characteristics were measured and compared. The slaughter value of the mirror strains tended to exceed that of the scaled type carps. For the calculated body indices (profile, cross-sectional, head and tail index) the influence of strain was statistically proven. Fillet fat content was significantly (P<0.01) affected by strains/ponds. The pH value of the fillet was significantly influenced by the strain as a fixed factor. Large, strain dependent variability was proven in fat content besides identical fillet dry matter contents. It was assumed that culture conditions and strain largely influence and lead to a marked variability of the body composition and flesh quality of the most important Hungarian fish species.
The surface microbial contamination is of great interest, since these microbes can be potential sources of food-borne diseases. The purpose of this study was to determine and compare the microbial surface contamination of sour cherry (Prunus cerasus L.) produced by integrated and organic cultivation methods in Hungary. The effects of the growing area, year, and cultivar were studied on 62 samples. According to the results, the average microbial contamination of sour cherry is within a certain range, independently from the cultivar, growing area, and year. The frequency distribution of the surface bacterial, mould and yeast counts also did not show significant differences between the growing methods or cultivars. Principal component analysis ranked the sour cherry samples into seven groups on the basis of the level of microbial contamination. The discriminant analysis proved the correctness of the grouping. The grouping was independent from cultivars, growing methods, and years. No examined food-borne pathogen Salmonella spp. or Listeria spp. were found on the surfaces of sour cherry.
Authors:A. Sebestyén, Zs. Kiss, B. Vecseri-Hegyes, G. Kun-Farkas and Á. Hoschke
Currently gluten-free beer is not produced in Hungary for coeliacs. The goal of our research was to develop brewery products made of domestically grown millet (Alföldi 1) and buckwheat (Oberon) that are similar to traditional beer of barley malt regarding taste, aroma, consistency, colour, foam stability and alcohol content.On a micromalting equipment malts were made of buckwheat and millet. Beer was produced on pilot plant scale (50 l) with decoction process (mashing program with rests at 50 °C, 65 °C and 72 °C) and was supplemented with a highly heat-stable bacterial α-amylase, a fungal α-amylase and β-glucanase. Malts were evaluated by congress mashing (extract content, extract difference, pH, and colour); wort and final beer analyses were performed as well (pH, extract, iodine test, FAN, colour, bitterness, alcohol and extract content). Finally, sensory characterization was carried out. Difficulties with lautering were encountered during the brewing process with buckwheat. The analytical results indicated that the buckwheat and millet beer had different values compared with a typical barley beer with regard to pH, FAN, fermentability, and total alcohol. The extracts of the buckwheat and millet wort were lower, resulting in a final attenuation of 61.5% and 73.2%.In laboratory experiments optimal temperature of β-amylase found in domestically grown buckwheat (64 °C) and millet (62 °C) was determined by detecting maltose production with HPLC. Data was used to set the rest temperature of the enzyme during mashing. Inhibiting effect of certain substances on proteolytic enzymes was investigated by measuring the extract, FAN, and soluble nitrogen contents. Inhibition was detected in case of both raw materials, although to a different extent. Inhibition is influenced by tannins and polyphenols found in the grain (Chethan et al., 2008).
The objective of this work was to assess the impact of various NaCl concentrations on Lactobacillus rhamnosus OXY viability after freeze-drying. Osmotic stress was applied during the exponential growth phase of bacterial culture. At salt concentrations between 0.2–0.5 M, a high biomass concentration and a significant increase in cell viability after lyophilisation was observed. An analysis of two-dimensional protein gels indicated the presence of shock proteins, for example, GroEL, ClpB, DnaK, TF, which provide resistance during freeze-drying and subsequent storage. On the basis of these results, it is recommended that lactic acid bacteria cultures be sub-lethally treated with 0.5 M NaCl before freeze-drying.
Authors:P. Penksza, R. sárosi, R. Juhász, K. Manninger-kóczán, B. Szabó-Nótin, L. Szakács and J. Barta
The aim of the present study was to investigate whether the Jerusalem artichoke powder produced by a simple drying method is suitable for replacing inulin in dairy products and in fat replacer mixtures. Rheological properties of milk drinks were tested by rotational method measuring the flow curve and fitting the Herschel-Bulkley model. The Jerusalem artichoke powder showed similar rheological behaviour as the commercially available inulin and proved to be a more effective thickener in milk drinks as indicated by the higher consistency values at the same concentration. Panelists found milk drinks prepared with Jerusalem artichoke powder to have similar sensorial quality as prepared with inulin. Fat replacer mixtures were tested by oscillatory tests using amplitude sweep method. The samples containing Jerusalem artichoke powder had lower complex viscosity and initial G’ and G” values indicating weaker gel forming properties compared to inulin. However, lower slope of G’ and G” indicated their better spreadability. The organoleptic texture properties of fat replacer prepared with Jerusalem artichoke powder proved to be slightly better than that of the inulin containing mixture. Based on our results, the Jerusalem artichoke powder seems to be suitable to replace inulin as a natural additive in certain food products.
Recently food-grade microemulsions have been of increasing interest to researchers and exhibited great potential on their industrial applications. The microbiological and quality characteristics of NuoMiGao, a traditional Chinese steamed rice cake, affected by a prepared food-grade monolaurin-containing microemulsion have been evaluated in this study. Microbiological analysis indicated that 0.05% microemulsion was comparable to 0.01% sodium dehydroacetate, extending the shelf-life by two days. The quality analysis showed that the addition of the microemulsion effectively prevented the hardening phenomena in rice cake; the lightness and yellowness were fairly stable while redness increased slightly (P<0.05); the lowered pH value and the prevention of moisture drop in rice cake were in agreement with the microbiological analysis and hardness trends.
Authors:G. Styevkó, Cs. Styevkó, Á. Hoschke and Q. Nguyen
Glycosyltransferase activity of Pectinex ultra SP-L (from Aspergillus aculeatus) commercially available enzyme preparation was studied in mono- and bisubstrate systems using different donors (maltose, lactose, and sucrose) and acceptors (fructose, galactose, glucose, maltose, mannose, xylose, lactose, and sucrose). Oligosaccharides consisting of three monomers were detected in the cases of maltose, sucrose, and lactose as monosubstrates, thus this preparation should contain glucosyl-, fructosyl-, and galactosyl-transferase activity. Generally, yields of oligosaccharides synthesized were higher in bisubstrate systems maltose:sucrose, maltose:lactose, and sucrose:lactose than on monosubstrates. Use of maltose:sucrose bisubstrate resulted new oligosaccharide(s) (fructosyl-maltose or glucosyl-sucrose). The optimal ratio of substrates in the case of maltose:sucrose was determined to be 1:9. Increase of the dry content of the reaction mixture induced the transfer reaction. The highest oligosaccharide content was obtained at 60% (w/v) substrate concentration. In the case of the optimal ratio and dry content, 4.02% (w/v) oligosaccharide (DP3) concentration was achieved. These oligosaccharides may alter prebiotic and biochemical properties in food applications.
Authors:A. Dutta, P. Gope, S. Banik, Md. Rahman, S. Makhnoon, M. Siddiquee and Y. Kabir
Milled rice from nine aromatic cultivars was evaluated for physicochemical, cooking, and antioxidant properties. Physical parameters measured were milling outrun, head rice yield (HRY), and appearance (size and shape). Cooking time, water uptake ratio and elongation ratio were determined to study their cooking quality. Chemical parameters included were amylose content (AC), protein content (PC), gel consistency (GC) and alkali spreading value (ASV). Total phenolic content (TPC) was measured using the Folin-Ciocalteu method, while ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), and 1,1-diphenylpicrylhydrazyl (DPPH) radical scavenging activity were used to study their antioxidant activity. This study revealed all rice cultivars, except Basmoti-370 and Gopalbhog, showed HRY. Besides, all rice cultivars displayed high protein content. Significant variations (P<0.05) were found in TPC and the antioxidant activities of the rice cultivars. The correlation coefficient between the TPC and the antioxidant activities was strong and statistically significant (P<0.05).
Authors:Ž. Kurtanjek, D. Horvat, G. Drezner and D. Magdić
Gluten proteins composed of gliadins and glutenins are important contributors to the wheat quality properties. Twenty-eight winter wheat cultivars differing in bread processing quality were collected at the experimental fields of the Agricultural Institute Osijek, Croatia, in growing season 2006/2007.The HMW-GS composition and gliadin contents were determined by SDS-PAGE and RP-HPLC, respectively, with the aim to determine their relationship with wheat quality properties. Based on gliadins and HMW-GS data for 28 wheat cultivars PLS models were developed for the prediction of 15 baking quality parameters.NIPALS algorithm was applied for the evaluation of the latent variables and regression coefficient parameters. The obtained 4-th order models have average coefficients of determination R2=0.80.Determined variable importance in projections (VIP) coefficients revealed that HMW-GS data have the dominant influence on the baking quality parameters. For extensographic and farinographic properties the Glu-D1 locus has the main VIP coefficient while Glu-B1 locus is the most important for the indirect quality parameters. The derived PLS models and VIP coefficients could be used in molecular based wheat selection and breeding program.
Authors:D. Radványi, R. Juhász, Sz. Kun, B. Szabó-Nótin and J. Barta
Elderberry pomace, by-product of juice pressing procedure, is still rich in biologically active compounds, especially antioxidants and phenolic compounds. The aim of the present study was to investigate whether elderberry pomace could be utilized as a source of natural colourings and preservatives. By a simple solvent extraction a proper food colouring could be produced from elderberry pomace characterized by similar colour values as pressed elderberry juice. A solvent ratio of 1:20 with 50% ethanol proved to be the optimal solvent extraction method to produce an extract rich in antioxidants showing inhibitory effect against Lysteria monocytogenes and Enterococcus faecalis. In elderberry pomace extract three main phenolic compounds: chlorogenic acid, rutin and coumaric acid have been identifed by HPLC analysis. Based on our results, elderberry pomace, a by-product of fruit processing technologies, seems to be suitable for developing natural food additives after appropriate clarifcation processes.
Authors:E. Bujna, F. Kukovics, Q. Nguyen and J. Rezessy-Szabó
Production of phytase by Aspergillus niger F00735 strain in submerged fermentation was studied. The effects of various natural substrates with different phytate contents on secretion of extracellular phytase were investigated and the rice flour with about 5 mg g−1 of phytic acid was found to be the best one. The repression effect of high levels of phytic acid or inorganic phosphorous in fermentation medium (corn flour, wheat grit, soy flour, etc.) on production of phytase was also observed. The optimal concentration of rice flour as main carbon sourc e was determined in combination with sodium nitrate. The maximal activity (≈1500 U l−1, 1.5 times higher than using basal medium) was achieved on the 7th day in media containing 7.12% (w/v) rice flour and 0.86% (w/v) sodium nitrate. Supplementation of fermentation medium with different surfactants such as Tween series (20, 40, 60, 65, 80, 85) and Triton X-100 up to 0.1% (w/v) had no significant effects on the secretion of phytase enzyme, meanwhile at concentrations higher than 0.2% (w/v), decrease in enzyme activity was observed.
Authors:D. Živković, S. Šobajić, M. Perunović and S. Stajić
The influence of seasonal variations on the chemical composition and composition of fatty acids in five commercially important freshwater fish species from the Danube: white bream, bream, vimba, zope, and Prussian carp, during May, July and September was determined. Changes in the chemical composition of meat of all examined species had the same tendencies. Water and protein content in the meat decreased, while fat content increased. The most frequent fatty acids in the meat of all the examined fish were the following: 18:1 n-9 (oleic), 16:0 (palmitic), 16:1 (palmitoleic), 18:2 n-6 (linoleic), 20:1 (eicosenoic), 20:5 n-3 eicosapentaenoic acid (EPA), 20:4 n-6 arachidonic acid and 22:6 n-3 docosahexaeonic acid (DHA). The content of saturated fatty acids (SFA) ranged from 25.03% to 32.43% and displayed a tendency to increase during the observed period. The total content of the n-6 group in the meat of Prussian carp was higher than in other species, which was probably a consequence of specific diet. The total content of n-3 fatty acids in the meat of white bream, bream, vimba and zope was the highest in May, and it declined during July-September. We can conclude that the meat of white bream and vimba contains high nutritional values in terms of EPA and DHA content. The n-3/n-6 ratio was also very favourable: 0.9 to 2.0 in the meat of white bream, bream, vimba and zope, with a clear downward tendency in the observed period.
Authors:R. Juhász, K. Horváth, I. Dalmadi, É. Andrássy, A. Salgó and J. Farkas
Effect of 60Co irradiation on wheat and white pepper grains were investigated in this study using Rapid Visco Analyser (RVA), near infrared reflectance spectroscopy and differential scanning calorimetry. Functional properties of wheat and white pepper were affected by irradiation indicated by a decrease in viscosity values. It was caused by changes of starch structure confirmed by the NIR spectra changes between wavelength 1560–1620 nm, which is the vibration of intermolecular hydrogen bonded OH groups in polysaccharides. The radiation used did not cause significant changes in the thermal properties. RVA proved to be useful for screening radiation induced changes in dry commodities of considerable large starch content on the basis of their rheological behaviour.
Authors:Á. Nagy, Z. Kovács, D. Szöllösi and A. Fekete
The potentiometric electronic tongue is a new and rapidly developing technique. However, the description of the exact working mechanism is still absent. An important part of this description is the effect of the sample temperature on the measurement results. The paper reported here gives a description of the effect of temperature on results obtained with an α-Astree potentiometric electronic tongue. The yielded model was used to perform a temperature correction as if the samples were measured at room temperature (25 °c).
Cities are responsible for about 30% of the energy consumed worldwide. Since 2007 more than 50% of the world population lives in cities, and urbanization is still growing. The energy-efficiency of cities is gaining greater importance today. The paper examines the possibilities of energy consumption reduction and optimization in cities. Various urban and architectural tools are described below that affect indirectly and directly the energy balance of cities. The possible ways of using renewable energy sources in cities have been analyzed. Ways and means of their use is analyzed in on-site, nearby and off-site systems.
In this study Trapezon’s result is generalized on bending oscillation of beams of constant thickness whose width varies in accordance with a fourth order parabola. The existence of a closed formula is shown, which offers solution not only for a fourth order parabola but for every power function describing the width of the beam. In particular, if the exponent is a power of 2 then also the closed form of the general solution can be given.
Managing waste becomes a much more complex task, when logistic changes have to be implemented to combine selective waste collection, needed to increase the rate of recycling, with traditional residual waste collection. This complexity is complicated further by the ever increasing choices of methods and technologies available for the treatment of collected waste.Using available resources efficiently, minimizing environmental effects and operation costs should be the guiding ideas behind optimization of a waste management system, even though often these ideas are in conflict with each other. In this phase of research those factors which have a major influence on system costs are analyzed.
Development of biomineralizing techniques requires new or borrowed methods, as well as instruments for the evaluation of the efficacy of the biomineralization. The aim of the research was to evaluate the appropriateness of two existing techniques for measuring the surface hardness and material loss of microbially treated porous limestone surfaces. Measurements were done with Duroscope, and with the peeling-tape method. The techniques were tested in a comparison trial, where different bio-based curing compounds were applied on porous Sóskút limestone slabs. Two of the bio-based, and the conventional compounds show higher development in the surface rebound values (86.67 to 201.1%) and higher decrease in material-loss (−39.5 to 96.3%) compared to the control specimen. Through statistical analysis of statistical samples with a high number of results, the suitability of the techniques was evaluated.
The municipality of Gyor participated in the last five years in two Intelligent Energy Europe projects (Pro Motion project, Travel Plan plus project), which aim was to deliver transport-sector energy savings by creating a new approach to site-based mobility management across Europe. During the development of the two projects there has been worked out two Local Travel Plans, one for the residential area Menfocsanak, in the city, Gyor and one for the educational institutions of Gyor. The first one is a so called ‘area travel plan’ and the second one is a so-called ‘work travel plan’. The aims of these studies were to reduce CO2 emission caused by private car users and to promote sustainable mobility choices for the residents of the area and for students. In order to solve the future mobility challenges in a sustainable way it is necessary to analyze the existing travel demand and modal-split caused by target groups (residents and students).It is important to develop Local Travel Plans for residential areas and schools, based on quantitative travel behavior data, which can be used for modeling of current and future transport to provide optimized solutions for daily mobility. It is very important to collect data from various sources according to the needed detail of a Travel Plan.
The energy and climate concept of the flagship research institute of the University of Pécs is the result of a three-stage development. The prototypical structures and building services of the first two concepts were developed in line with the financial circumstances and grants and the rationalized third concept became an object for construction research. Through the expansion of the building services and energy supply systems, the building itself has become a ‘measuring apparatus’ for sustainable building construction.
An essential input for environmental studies, especially for hydrological simulations is the soil information, which is usually provided by spatial soil databases. Despite the growing number of related analyses little is known about the uncertainty associated to databases. This study aimed to evaluate this issue. (i) the World Soil Classification System was used to classify soil horizons of the Unsaturated Soil Hydrologic Database of Hungary, (ii) the resulting soil classes were statistically analyzed, (iii) various static measures were derived and dynamic numerical simulations were carried out to assess the uncertainties of the classification method from hydrologic viewpoint. The results question the reliability of the FAO method.
In working with soft soils from tailings unusual material behavior was observed, which could not be explained, using conventional geotechnical models. Therefore the scope of the research has been widened, and experiments with viscous material models began. The aim of the research was to interpret the rheological models indicating viscous behavior into geotechnical practice and looking up existing geotechnical models, which include viscosity and examining their applicability in everyday praxis.
In this paper the results of an investigation about steel fibers bond strength in mortar matrix are presented. Pull-out tests were made with four different types of fibers (hookedend, crimped, flat-end, anchoraged), the fibers were embedded individually into a cement based sample with three different embedded length (10, 15, 20 mm). Another variable parameter of the experiment was the strength of the matrix (three different mixture were used), and hooked-end fibers with higher tensile strength and zinc surface coating were tested also. During the tests pull-out force and displacement were measured.
This paper describes wood-concrete structural members in which the interlayer connection is achieved with adhesives, by overlaying the fresh concrete over the top of a wood layer to which moisture tolerant adhesive coating was applied a short time before the casting. Laminated wood-concrete structural members could be built as beams or slabs. Experimental results presented on eight laminated wood-concrete beam specimens subject to static loading indicate that the load capacity of the laminated wood-concrete beams exceed the performance of the classical wood-concrete beams which use shear notches cut into the wood for the interlayer connection.
The numerical analysis of a gradiometric coil arrangement has been performed and the response of a metallic material in the vicinity of the coil system has been examined. The system has been excited by a bandwidth limited step function, thus the step response of the different target materials can be measured on the gradiometer. The 3D numerical model has been prepared in the CST EM Studio environment and has been solved by the finite element method. The simulations have been executed for different target materials, i.e. aluminum, steel, stainless steel and in order to unveil the specific contribution of the magnetic permeability and the electric conductivity to the step response for four fictive materials. The results show that the step response is an appropriate parameter to distinguish between the target materials and to provide information about the sensor to target distance.
During the architectural planning of modern, complex, block-structured, large-area located, but still landscape-harmonized health-care buildings, the key is the optimal positioning of the blocks and functions, simultaneously ensuring the most-effective backup-paths for any single transportation route failure in the buildings to speed up the operation, reduce the maintenance costs and especially to improve the satisfaction of the patients. Mathematical statements are to be solved with multiple serious challenges when formulating the positioning problem with resilience to the buildings for any single failure. An innovative graph representation referred as link doubling is presented where Minimal cost multi commodity flow problems could be solved.
Authors:István Háber, István Kistelegdi, Tamás Bötkös and István Farkas
The most common way to measure solar radiation is the horizontal global irradiation measured by a pyranometer. To use the collected data in photovoltaic energy-yield prediction a mathematical model can be made from average data’s of more years. These global horizontal values to be used on tilted surfaces like a solar module, should be transformed, according to the incident angle of the solar beam. But there is a diffuse component also, which has to be determined, because it should be transformed in different way. This work is a case study, where data modeling and the transformation process will be shown using the data collected for Pecs/Hungary, and transformed for an existing site on Komlo, the RATI Ltd’s zero energy factory and also a LabView program has been made based on these data, to be used in the complete ‘heat transfer based photovoltaic-yield model’.
A numerical procedure is presented for the study of the failure mechanism of reinforced concrete sections of arbitrary shape in biaxial bending with axial force. The procedure is a fiber model, which allows to compute the moment-curvature diagram and the interaction domains using non-linear constitutive laws, also with softening post-peak branch for concrete. The numerical technique is able to find the position and the orientation of the neutral axis that determines a resultant moment, which acts along a predefined orientation angle. Analytical moment-curvature diagrams and interaction domains are compared with data published in the literature.
The aim of this paper is to give a unified comparison of non-overlapping domain decomposition methods for solving magnetic field problems. The methods under investigation are the Schur complement method and the Lagrange multiplier based finite element tearing and interconnecting method, and their solvers. The performance of these methods has been investigated in detail for two-dimensional magnetic field problems as case studies.
Authors:Balint Baranyai, Balint Póth and István Kistelegdi
Due to negative environmental changes and the energy supply problems of the society the EPBD 2010/31/EU prescribes for EU member states to ensure that by 2021 all new buildings are nearly zero energy buildings. The Energydesign® research team of the University of Pécs has developed a research-design method applicable for building climate, energy, aerodynamic and architectural technology modeling of smart energy-plus buildings. This problem-solving matrix arranges the systematic structured planning process, calculations, complex analysis, dynamic energy-climate and computational fluid dynamics simulation control of buildings through a finite number of algorithmic steps. The description of the logged design steps is meant to be an instructional process-guide, the Energydesign Roadmap.
The paper presents an appropriate method for comparing different heuristics or metaheuristics. The necessity of comparison is unquestionable, because the evaluation of competing techniques is an actual topic and results are highly important. In resource-constrained project scheduling the adaptation of the appropriate elements of the very rigorous protocol is necessary just as in the case of testing a new drug, or comparing the effects of different drugs. The problem is widely discussed by the heuristic community and thus it cannot be only connected to the resource-constrained project scheduling problem. Until now the result of these researches are without real detectable results. When, for example, we use stochastic searching methods in the resource-constrained makespan minimization (namely heuristics or metaheuristics with several tunable parameters and starting seeds), then the usual presentation practice: ‘one problem — one result’ is extremely far from the fair comparison. From statistical point of view, the minimal requirement of the fair comparison is a small-sample for each investigated approach and an appropriate nonparametric-small-sample-test according to the experimental design theory and the very slowly changing result presentation standard. The viability and efficiency of the proposed statistically correct and bias-free methodology is demonstrated using the hardest subset of the well-known J30 set from Project Scheduling Problem Library to decide, which of two selection operators is better in a harmony search metaheuristic frame. An appropriate test of tests, which is able to analyze from statistical point of view the combination of independent tests, or in other words, the result on the test set as a whole, is under development, and will be presented in a forthcoming paper.
Estimation of ecological water demand of groundwater dependent ecosystems is essential in quantitative status assessment of groundwater bodies. In the Hungarian River Basin Management Plan a top-down approach was applied that — due to its resolution and data distribution — proved to be inaccurate in case of critical areas. A more sophisticated method was developed in cooperation with the Institute of Ecology and Botany of the Hungarian Academy of Sciences, which — as a bottom-up approach — is appropriate to calculate groundwater demand of habitats more precisely at regional or even local scale. Comparison of the methods is illustrated in the Nyírség-Lónyay and Rétköz groundwater body group.
Authors:I. Tamáska, Z. Vértesy, A. Deák, P. Petrik, K. Kertész and László Biró
Bioinspired 1+2D nanoarchitectures inspired by the quasi-ordered structures occurring in photonic nano-architectures of biological origin, like for example butterfly scales, were produced by depositing a layer of SiO2 nanospheres (156 nm and 292 nm in diameter) on Si wafers, over which a regular multilayer composed from three alternating layers of SiO2 and TiO2 was deposited by physical vapor deposition. Flat multilayers were deposited in the same run on oxidized Si (324 nm SiO2 thickness) for comparison. Different types of disorder (in plane and out of plane) were purposefully allowed in the 1+2D nanoarchitectures. The positions of the specular reflection maxima for the flat multilayer and for the two different bioinspired nanoarchitectures were found to be similar. Additionally to this, the bioinspired nanoarchitectures exhibited angle independent diffuse reflection too, which was absent in the flat multilayer. Different model calculations were made to explain the specular and diffuse optical properties of the samples. Satisfactory agreement was obtained between experimental data and model calculations.
Authors:V. Koval, Y. Yasievich, M. Dusheyko, A. Ivashchuk, O. Bogdan and Y. Yakymenko
Silicon nanocomposites (nc-Si) with rare earth metals (REM) were synthesized by electron-beam evaporation. The structure of nanocomposites was studied by atomic-force microscopy. The size of nanocrystallites was about 10–40 nm. Also chemical composition of obtained material was examined. The distribution of rare earth elements (REE) was uniform in film thickness, but it was characterized by a presence of maximum peak at the interface film-substrate. In the work the electrical and optical properties of nanocomposites Si:REE were investigated. Silicon nanocomposites with Eu or Y were characterized by high sensitivity to visible radiation. The ratio of dark to light resistance was achieved to 2 orders of magnitude, making this material very promising to use in thin-film photosensors. After deposition of nanocomposites Si:REE on silicon substrate, the heterojunction was formed at the interface film-substrate, for which the sensitivity to visible radiation was observed too (1–2 mA/lmV). Also, the presence of photovoltaic effect in such structures was shown, so they can be the basis of cheap thin-film solar cells, using the relevant design solutions.
A numerical study of the thermodynamic properties of a superconducting quantum cylinder in a longitudinal magnetic field is carried out. Closed-form expressions for the critical temperature, the free energy, the heat capacity jump, and the magnetization difference between the superconducting and normal phases as functions of the nanotube parameters are obtained in limit cases.
Authors:K. Ditrói, D. Kleiner, A. Böszörményi, K. Szentmihályi and H. Fébel
Hemp seed and hemp seed oil can supply us with many important substances. Their essential fatty acid compositions are favourable, but they may contain non-psychotropic cannabinoids. Emerging data show that these components can influence the health status of the population beneficially. Some data also showed trace amounts of tetrahydrocannabinol in seed oils, the main psychotropic cannabinoid that is contraindicated.Our aim was to examine cannabinoids and fatty acid composition as well as metal and non-metal element compositions in products, like hemp seed oil and chopped hemp seed capsule.The cannabinoids were separated by thin layer chromatography. Fatty acid composition was determined with gas chromatography, and elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sn, Sr, V, and Zn) were measured by inductively coupled plasma optical emission spectrometric method. Selenium was determined with polarographic analyser.Cannabinoids were not detectable by thin layer chromatography, so hemp seed oil, as well as the capsule, have no psychotropic adverse effect. Our data showed that hemp seed contains essential fatty acids close to the recommended ratio. The B and Se concentrations of the oils and the P concentration of the capsule are also relevant.
Authors:J. Lapa-Guimarães, P.E. Felício and E. Contreras Guzmán
The leaching of soluble compounds reduces the efficiency of chemical indices for freshness when fish is stored in ice. The objective of this study was to evaluate whether chemical indices for freshness evaluation of squid (Loligo plei) could be improved by expressing their contents as percentages of the non-protein nitrogen (NPN). The contents of NPN, free amino groups (FAG), trimethylamine oxide (TMA-O), trimethylamine (TMA), volatile basic nitrogen (VBN), ammonia (AMM), urea and free tryptophan (FT) were periodically determined in squid muscle during 16 days of storage in ice. The VBN, AMM, TMA, urea and FT contents in squids, when expressed as mg/100 g, did not distinguish between squids stored in ice for 1 or 2 weeks. However, when the contents of VBN and AMM were expressed as percentages of the NPN, it was possible to distinguish between squids stored for 1, 4 and 7 days. Free tryptophan was the most efficient quality index for L. plei, allowing accurate discrimination of squids stored in ice for 02-2, 4, 7–10, 13 and 16 days.
Authors:H. Orak, H. Yagar, S. Isbilir, A. Demirci and T. Gumus
In the present study, the antioxidant and antimicrobial activities of three tea (Camellia sinensis) types (white tea — WT, green tea — GT, and black tea — BT) were compared and the relationships between total phenolic, tannin and flavonoid contents were determined. Regardless of the assays used, the highest total phenolic content (313.3±1.41 μg GAE/mg extract), total flavonoid (16.98±0.27 μg QE/mg extract) and total tannin content (266.79±2.59 μg TAE/mg extract) were determined in green tea extract, which also demonstrated the highest antioxidant capacity. Black tea extract showed the lowest phenolic content and antioxidant capacity. The EC50 value of DPPH scavenging activity was in the order of: ascorbic acid >GT>BHA>WT>BT>BHT. While the tea extracts exhibited antibacterial activity against Staphylococcus aureus, no inhibitory effects were observed against Escherichia coli and Salmonella enteritidis. All extracts exhibited antifungal activity against two afl atoxigenic moulds Aspergillus parasiticus NRRL 2999 and NRRL 465. The antibacterial activity of tea extracts decreased in the following order: GT>WT>BT DPPH scavenging activity strongly correlated with total phenolic content, reducing power, antimicrobial activity against S. aureus, A. parasiticus NRRL 2999, A. parasiticus NRRL 465 (P<0.05). These data suggest that green tea extract is more effective than white and black tea extracts as a potential source of natural antioxidants.
Authors:I. Saoud, L. Hamrouni, S. Gargouri, I. Amri, M. Hanana, T. Fezzani, S. Bouzid and B. Jamoussi
The chemical composition, phytotoxic and antifungal activities of the essential oils isolated by hydrodistillation from the aerial parts of Tunisian thyme were evaluated. In order to find best results, different variables (i.e. provenance and phase of plant development) were considered. The chemical composition analysed by gas chromatography/mass spectrometry (GC/MS) revealed variability among provenances displaying interesting chemotypes and that carvacrol (63–84%), limonene (5–10%), δ-terpinene (0–7%), and β-myrcene (0–7%) were the main components. Antifungal ability of Thymus capitatus essential oils was tested by disc agar diffusion against five phytopathogenic fungi: Fusarium avenaceum, F. culmorum, Microdochium nivale var. nivale, Alternaria sp., and Bipolaris sorokiniana. High antifungal activity was observed for the essential oil isolated at the post-flowering development phase for the Bekalta provenance. There was no difference in the antifungal activities of oils isolated at the flowering phase from the other provenances. Thyme essential oils showed high level of weed-killer activity as well against Sinapis arvensis.
The procedure involving water and water-methanol extraction, RP-HPLC-C18 column chromatography with PDA detection was developed for determination of cinnamic acid and benzoic acid derivatives in grapevine’s dietary supplements (LV, RW, VIN, VIC, and DK) available on the Polish market. Phenolic acids were analysed before and after acidic and basic hydrolysis and identified against standards. Totalamount of studied phenolic acids determined by HPLC-PDA was compared with total polyphenols content (TPC) by Folin-Ciocalteu method. The average content of studied phenolic acids (70.54±0.21; 122.95±0.49; 87.67±0.10; 132.21±0.24; 266.78 ±0.39, and 18.16±0.09 mg/100 g d.m. (dry mass) for LV, RW, VIN, VIC, DK, and WW, respectively) were higher than the TPC (1489.91±0.39, 1648.19±0.14, 1574.38±0.33, 1643.64±0.12, 1984.75±0.97, and 715.55±0.36 mg/100 g d.m. for LV, RW, VIN, VIC, DK, and WW, respectively). The new developed method was validated for specifi city, repeatability, and accuracy and can be suitable for routine quality and quantity analysis of dietary supplements containing grape vine (Vitis vinifera).
The aim of this paper was to determine the causes of spoilage and odorous compounds in two different lots of traditional Friuli sausages produced by two small-scale facilities in San Daniele del Friuli. In spoiled sausages the water activity (Aw) was higher than in unspoiled sausages (0.94 vs. 0.91). Moreover, the pH of the spoiled tested sausages remained high despite the presence of acidifying bacteria (6.5±0.4 log CFU g−1), such as lactic acid bacteria (LAB) and coagulase negative catalase positive cocci (CNCPC). Conversely, in unspoiled sausages the pH value was 5.5±0.02. For this reason, the spoilage (mephitic type) can be attributed to the high pH (6.3±0.2 units) of the pork meat used, which was classified as a dark, firm, dry type (DFD), to the high Aw, and to the activity of LAB, CNCPC cocci, and Enterobacteriaceae. Because of the high pH and the lack of naturalor added sugars, these bacteria degraded the proteins via amino acid metabolism to produce ammonia, hydrogen sulphur, and methanethiol, which were responsible for the mephitic and putrid odour of the sausages.
Authors:Cs. Dobolyi, F. Sebők, J. Varga, S. Kocsubé, G. Szigeti, N. Baranyi, Á. Szécsi, B. Tóth, M. Varga, B. Kriszt, S. Szoboszlay, C. Krifaton and J. Kukolya
Climate change affects the occurrence of fungi and their mycotoxins in foods and feeds. A shift has recently been observed in the presence of aflatoxin producer Aspergillus spp. in Europe, with consequent aflatoxin contamination in agricultural commodities including maize in several European countries that have not faced with this problem before, including, e.g. Northern Italy, Serbia, Slovenia, Croatia and Romania. Although aflatoxin contamination of agricultural products including maize is not treated as a serious threat to Hungarian agriculture due to climatic conditions, these observations led us to examine the mycobiota of maize kernels collected from Hungarian maize fields. Using a calmodulin sequence-based approach, A. flavus isolates have been identified in 63.5% of the maize fields examined in 2009 and 2010, and 18.8% of these isolates were found to be able to produce aflatoxins above 5 μg kg−1 on maize kernels as determined by ELISA, HPLC-FL, HPLC-MS analyses and SOS-Chromotest. These data indicate that aflatoxin producing Aspergilli are present in Hungarian agricultural fields, consequently climate change with elevated temperatures could lead to aflatoxin contamination of Hungarian agricultural products, too.
Authors:F. Pallottino, C. Costa, F. Antonucci and P. Menesatti
In food science, colour is a fundamental property for the evaluation of freshness, quality and conformity. One of the most important attributes indicating sweet cherry freshness is stem colour and shape. Fruit post-harvest cool storage retards respiration and colour ripening changes. The common technology of refrigeration is based on active cooling determining high evapotranspiration for the passage of air over the products surface. An innovative preservation system, such as the Passive Refrigeration System (PRS™), could guarantee perfect shelf-life preservation maintaining optimal temperature and relative humidity close to 100%, minimizing colour changes in medium-long storage range. There is the need to numerically quantify cherry stem thickness and colour changes to compare fruit postharvest conditions under the two systems. The use of the Thin-Plate Spline 3D warping (TPS3D) in the 3-dimensional-RGB colour space allowed an efficient colour calibration. Sweet cherry stem images belonging to the two different storage systems (active and passive refrigeration) were acquired before and after 7 days to preservation through a professional high resolution scanner. Thickness and colour (after calibration) were measured. Results indicate, in terms of sweet cherry quality of preservation, that the ones preserved in passive refrigerator after 7 days appears similar to the fruits at the beginning of the experiment.
Pedestrians are vulnerable transport participants, and their movement analysis is always an up-to-date issue. The paper tries to present the zebra crossing without traffic lights (in the following un-signalized) on one-way one-lane roads. The video opened up new dimension to evaluate some parameters (gap time, speed distribution). The measured and the estimated parameters were used in the simulations. With help of the simulation the paper aims are to analyze the influence of pedestrians and cars on crossing movements. The paper describes that the relationship between delay, volume and pedestrian volume could justify the establishment of the signalized control.
Authors:Georgina Tóth, Ágota Drégelyi-Kiss and Béla Palásti-Kovács
The micro-geometrical properties of cutting surfaces can be quite different. The various surface-finishing processes remarkable differ from each other regarding the movements and the used tools. There are some further influential parameters, including the edge formation and the edge geometry of tools, the sharpness and the wear (cutting time) of the edge-part machined the surface.In the present work comparing examinations were performed on surfaces made with various machining processes. The integrity of differing surface micro-geometries was analyzed with the measurements of surface parameters, as well as with the calculation and discussion of statistical features of the results.Results show that the parameters measured on the same surface may differ significantly depending on surface machining and the state of the tools.
Authors:Miklós Kuczmann, Tamás Budai, Gergely Kovács, Dániel Marcsa, Gergely Friedl, Péter Prukner, Tamás Unger and György Tomozi
In the frame of the project TÁMOP 4.2.2.A, at the Széchenyi István University, the goal is to work out a new finite element package for the simulation and optimization of permanent magnet synchronous motors. These motors are then used to drive new electric cars. The aim of the two dimensional package is the fast numerical modeling of these electric devices by the use of free tools presented in the paper. Of course, the software is aimed to use it in the simulation of other devices, and three dimensional problems, as well.