EJPAU, 2010, Volume 13, Issue 1

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13(1) #02
27 Jan 2010
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Among of 100 of yeast isolated from Egyptian soils and tested for their β;-galactosidase (β-gal) activity, the highest producer was characterized and identified as Rhodotorula ingeniosa .This enzyme was found to be intracellulary produced, therefore permealization treatments to release the enzyme in a good yield was noticed when homogenization with sterile sea sand under cooling was employed as compared with chemical treatment. The enzyme was maximally produced when cellobiose at 1% final concentration and ammonium suphate at 1.5% final concentration were employed. The enzyme was partially purified with ammonium sulphate followed by Sephadex G-100 column chromatography. Some properties of the purified enzyme including the Effect of pHs, Effect of temperature Effect of reaction periods, and Effect of metal ions on the activity were estimated. On the other hand the use of this enzyme in ice milk production was studied. Different concentration of the enzyme was added to fresh pasteurized milk. Results clear indicate that the addition of the enzyme to ice milk mixes increased the sweetness although the organoletic properties of the resultant ice milk  was slightly decreased.

13(1) #12
18 Mar 2010
Food Science and Technology
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Raw materials, semi-products and residues of five successive Pilsner beer production processes of the same brand were examined for the histamine content. A high level of histamine was noted in raw materials, hop in particular. In spite of various levels of histamine in successive processes the changes noted in its content were correlated. The highest variability was noted for the fermentation process. It is highly probable for the microbiological contamination of raw materials, particularly yeasts, to be responsible for changes in histamine content to a greater extent, that the initial histamine level in raw materials.

13(1) #03
02 Feb 2010
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The paper examines the level of the cost efficiency of the Polish non-life insurance industry in the period 2003-2007. The analyzed period characterizes intensive restructuring due to the preparation and first years of operations on the common pan-European financial market. Relatively low density and penetration of insurance services in Poland were important motivations for foreign insurance companies to enter the Polish market. The 80% share of foreign capital in the Polish insurance sector resulted in reduction of dominance of the main state-owned insurer and the increase of competition on the Polish non-life insurance market. The examination was conducted on the group of 34 Polish insurers based on their annual data provided by the Polish Insurance Chamber. The stochastic frontier analysis showed that during this period the average level of cost efficiency was decreasing from 49% to 43%. The regression analysis indicates that operational costs have negative impact on the level of efficiency. Additionally firms lowered their efficiency in a result of reduction of the market concentration and increase of competition, which is in accordance with the Structure- Conduct-Performance (SCP) paradigm. Higher acquisition costs are expected to be responsible for the lower level of cost efficiency. Economic downturn is expected to have a positive impact on the efficiency. No correlation between efficiency and insurer’s size could indicate an absence of scale effects in the non-life insurance sector in Poland.

13(1) #04
17 Feb 2010
Animal Husbandry
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Two stage experimental fattening was conducted on 64 young Polish Holstein-Friesian bulls of black and white type. Trial group was fed with concentrate containing 23.5% of corn dried distillers grain with solubles (DDGS) from 250 to 400-420 kg body weight, and 13.5% DDGS in finishing stage up to 570 kg body weight. The effect of extracted rapeseed meal replacing with corn DDGS on performance, carcass characteristics and fatty acid profile of intramuscular fat in muscullus longissimus dorsi was determined. Dried distillers grain with solubles supplementation caused significant (228 g) increase of average daily gain (ADG) in the first stage of experiment. Feed conversion rate (FCR, gain: feed) in trial group was 0.036 kg higher in the first, and 0.007 kg lower in the second stage of experiment comparing to the control group. Improved ADG and FCR in the first stage involved the 22 days decrease of experimental fattening period. Carcass dissection results and prime cuts percentage did not differ between trial and control group in none of fattening periods. Introduction of corn dried distiller grain with solubles into feed concentrate indicated an improvement of fatty acid composition, including increased level of C18:2 fatty acid in intramuscular fat.

13(1) #07
05 Mar 2010
Food Science and Technology
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The nutritional values of foods especially green leaves vary a great deal, depending on the types or variety of plant and growing condition. The aim of this work was to evaluate the boron content of selected aquatic weeds found in Nigeria. Carmine method was employed in the analysis. From the analytical result, it was observed that there were differences (57–81 mg 100-1g DM) in the values obtained. Comparing our results with pacific vegetables there were variability which might be due to the analytical method used, the soil and water contents and geographical origin. It could be concluded that these aquatic weeds might be good sources of boron for animals and humans.

13(1) #10
15 Mar 2010
Food Science and Technology
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The aim of this study was to determine the effect of cheese addition on physicochemical and sensory changes in wheat bread, which were observed during 3 months of frozen storage. Cheese was added at 1, 5 and 10% levels to dough. The samples, after baking, cooling and freezing, were kept in the temperature of -25°C. The quailty of fresh bread and after 1, 2 and 3 months of frozen storage was estimated by determination of mass change, acidity, hardness, cohesiveness, springness, resilience, gumminess, chewiness and sensory evaluation.
Along with the increase of length of frozen storage period, weight losses of the examined samples, irrespective of the quantity of cheese addition, were increased. Whereas the presence of cheese in wheat bread caused a higher level of acidity. In the organoleptic assesment fresh bread and bread after 1 month of storage were obtained higher score, thus it can be classified among  the 1st class quality products. After 2 months of storage only the loaves with 5% cheese were assigned to the 1st class in sensory analysis.
On the basis of results obtained it was found that the addition of cheese resulted in the increase of hardness, cohesiveness, resilience, gumminess and chewiness and the decrease of springiness. Comparing the change of texture parameters of fresh and storing samples was affirmed the significant differences. Only the samples of bread with 1% and 5% addition of cheese did not show the essential change of hardness after whole their period the storage. The statistical analyses showed that acidity of bread correlated with texture parameters, including hardness and gumminess. It has been also found the high values of correlation coefficients between gumminess and chewiness, cohesiveness and resilience, hardness and gumminess/chewiness.

13(1) #11
17 Mar 2010
Agricultural Engineering
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The paper presents results of modelling of quality changes in a muliticomponent non-homogenous granular mixture during mixing in an industrial worm mixer. The analysis was carried out for three granular mixtures: nine-component, ten-component and twelve-component. Modelling was performed with the use of nonlinear regression. Dependent variable was a residual sum of squares (mixture quality parameter), whereas independent variables were: number of components and mixing time. Two-dimensional dependence was constituted by square function formula. The aim of the study was to describe quality changes of muliticomponent, non-homogenous granular mixtures (nine, ten and twelve – component) during mixing in a vertical mixer with worm agitator, with the use of nonlinear regression model. Atypical aspect of the mixing process was a specific recirculation of the mixed components with the use of bucket conveyor during the process.

13(1) #09
09 Mar 2010
Agricultural Engineering
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The shear strength and shear energy per unit area as well as force and energy for picking of flowers are important parameters to design and develop harvesting mechanisms. In this study shear strength and shear energy per unit area of saffron (Crocus sativus L.) stalk were determined as a function of bevel angle and shear velocity. Also, picking force and energy of saffron flower were determined as affected by tension velocity and age of plant. The experiments were conducted on samples selected from fields of Kashmar. The results showed that with an increase in bevel angle of cutting blade from 17° to 24°, the shear strength and shear energy per stalk area increased significantly from 0.13 to 0.19 N/mm2 and 0.305 to 0.443 mJ/mm2, respectively. With increasing cutting rate from 20 to 200 mm/min the average values of shear strength and shear energy per stalk area decreased significantly in the range of 0.179 to 0.158 N/mm2 and 0.467 to 0.340 mJ/mm2, respectively. Further increase in cutting velocity in the range of 200 to 500 mm/min was not decreased shear strength and shear energy significantly. The average values of picking force, tensile strength and energy per unit area were increased from 0.339 to 0.459 N, 0.169 to 0.229 MPa and 0.473 to 1.914 mJ/mm2, respectively when tension rate increased from 50 to 500 mm/min. The age of plant had not significant effect on picking force and energy and tensile strength. The obtained data was useful in designing and development of saffron harvesting mechanisms.

13(1) #08
08 Mar 2010
Wood Technology
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Within this study the applicability of complete substitution of wood chips in the core layer of particleboards using straw particles of an evening primrose species (Oenothera paradoxa Hudziok) was investigated in boards resinated with UF, MUPF and PMDI resins. Conducted investigations showed that complete replacement of wood chips with straw particles from an evening primrose species in the core layer of boards, irrespective of the type of the binding agent, causes a reduction of their strength and water resistance. However, the application of an adequately high resination rate, dependent on the type of adhesive resin, makes it possible to manufacture boards meeting the requirements of a respective standard EN – 312.

13(1) #13
22 Mar 2010
Environmental Development
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Laboratory experiment was carried out on light dusty clay, into which two herbicides: Izoturon 500 SC (composed of isoproturon only) and Rokituron D 470 SC (composed apart from isoproturon of 2,4-D and dicamba), were introduced in the following doses: recommended field dose (FD), tenfold higher dose (10FD) and one hundredfold higher dose (100FD). The amount of isoproturon introduced together with Izoturon 500 SC and Rokituron D 470 SC was the same, which allowed for assessing the effect of 2,4-D and dicamba on the rate of isoproturon decay in soil as well as for evaluating the modification of changes in soil biochemical parameters induced by isoproturon introduction into it by 2,4-D and dicamba. During the experiment, the content of isoproturon and its metabolites: MDIPU, DDIPU and 4-IA, and of dicamba and 2,4-D in soil as well as the activity of catalase, dehydrogenase and nitrate reductase. Isoproturon DT50 in soil ranged between 9.7 and 18.5 days and rose together with a dose increase. MDIPU, i.e. the metabolite produced in result of the N-demethylation of isoproturon, was detected as early as on day 1 of experiment. Other determined metabolites were detected in successive measurement times. Moreover, isoproturon addition to soil decreased the activity of examined enzymes as well as the value of AEC. It was also found that 2,4-D and dicamba addition slowed down the rate of isoproturon decay in soil as well as intensified the inhibition of nitrate reductase and dehydrogenase activity in soil and levelled the inhibition of catalase activity in soil induced by isoproturon.
Basing on the carried out research work, it can be stated that the best indicator of soil contamination with isoproturon appears to be the AEC value, which was negatively correlated with the content of isoproturon and MDIPU in soil, with the content of these compounds amounting respectively to 40 mg kg-1d.w. soil and 2.2 mg kg-1d.w. soil when the value of AEC decreased rapidly.

13(1) #06
03 Mar 2010
Veterinary Medicine
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The dorsal notch and incomplete ossification of the occipital bone in the 8 month old puppy of Papillion dog was described. Although at occipital dysplasia, the neurological signs did not occur. On the base of the standart craniometrical measurements, the type of the skull was idnetyfied as mesocephalic. The height of dorsal notch was 5.28 mm and the foramen magnum index equals 162.54 and dysplasia index 54 in post mortem examination. The literature is a source of various opinions about dorsal notch. Some authors qualified this as anatomical variation, but others suggest the dorsal notch occurs for example in cases of occipital hypoplasia and syringomyelia.

13(1) #01
26 Jan 2010
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The study fulfilled under the frame of the project of 6th General Program of EC showed that partially mechanized logging methods prevailed in Lithuania and other countries of Central Europe. The main problem is logging in wet leafy forests and the transportation of big diameter trunks. Forest soil protection recommendations for logging are predicted in legal documents of Austria, Lithuania, Poland, Hungary and Germany. Only in Lithuania and Germany the logging employs skid road system in the forest.

13(1) #05
02 Mar 2010
Agricultural Engineering
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The subject of the present paper are the problems of generating driving forces on recreational grass by traction tires of grass type. The studies examined changes of traction forces generated by these tires on turfgrass utilized with varying intensity. An analysis is presented of changes in the maximum traction forces, friction coefficients, maximum shear stress and compaction. Among the tested tires, the largest traction forces were generated by a tire of 18×9.5-8 for the whole range of changes of perpendicular loads.

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