939 resultados para Effect of water


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Ready to eat pasta meals are an important segment of convenience food, but these products are subjected to significant changes in physico-chemical properties during storage, which reduce their acceptability at the time of consumption. A deep understanding of the properties of the single phases, their dependence upon formulation, and the changes they undergo during storage is very important to intelligently intervene on products properties to improve their quality at the time of consumer’s consumption. This work has focused on the effect of formulation on physico-chemical properties of pasta and tomato sauce with a special focus on mechanical/rheological attributes and water status. Variable considered in pasta formulation were gluten, glycerol and moisture content and their effect was studied in both freshly cooked or shelf-stable cooked pasta. The effect of multiple hydrocolloids (at different levels) was considered in the case of tomato sauce. In the case of pasta, it was found that water content was indeed a very important variable in defying pasta mechanical properties and water status. Higher moisture contents in pasta resulted in softer samples and reduced the changes in physico-chemical parameters during storage. Glycerol was found to favor water uptake and to soften the pasta matrix, acting as plasticizer and increasing molecular mobility. The addition of gluten hardened pasta but did not affect the water status. The combination of higher amount of gluten (15%, g gluten / 100 g product) with higher moisture content (59-65%, g water / 100 g product) were found to minimize the physico-chemical changes occurring in RTE pasta meals during storage, improving quality at longer storage times. Hydrocolloids added into tomato sauce modulated its mechanical attributes and water status in very different manner, depending on hydrocolloid type and concentration. This may allow to produce tomato sauce for different applications and that are expected to have different performance if placed in contact with pasta in a RTE meal. Future work should include an investigation of how the interaction between the two phases (pasta and sauce) can be modulated and controlled by controlling the properties of the single phases with the goal of obtaining highly acceptable products also at longer storage times.

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The purpose of this investigation was to study the dissolution behavior of paracetamol and ibuprofen in the presence of a range of selected potential excipients. First, a pH-solubility profile was generated for both drugs, and the effect of changing hydrodynamic conditions on the intrinsic dissolution rate was investigated. It was established that both drugs dissolved according to the diffusion-layer model. Paracetamol solubility (approximately 20.3 mg mL -1) did not vary from pH 1.2-8.0, corresponding to the in vivo range in the gastrointestinal tract. Ibuprofen had an intrinsic solubility of approximately 0.06 mg mL-1, and pKa was calculated as 4.4. Second, the effects of selected potential excipients (lactose, potassium bicarbonate, sodium bicarbonate, sodium chloride, and tartaric acid) were evaluated by measuring the effect of the inclusion of each additive in the dissolution medium on drug solubility, drug intrinsic dissolution rate, and solution viscosity. The results were evaluated using the diffusion-layer model, and it was determined that for paracetamol, the collected data fitted the model for all the excipients studied. For ibuprofen, it was found that there were differences between the excipients that raised the solution pH above the pK a to those that did not. For the excipients raising the pH above the pKa, the effect on intrinsic dissolution rate was not as high as that expected from the change in drug solubility. It was postulated that this might be due to lack of penetration of the excipient into the drug boundary layer microenvironment. Formulators may calculate the effect of adding an excipient based on solubility increases but may not find the dissolution rate improvement expected. Copyright © 2005 Taylor & Francis Inc.

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Increasingly erratic flow in the upper reaches of the Mara River, has directed attention to land use change as the major cause of this problem. The semi-distributed hydrological model SWAT and Landsat imagery were utilized in order to 1) map existing land use practices, 2) determine the impacts of land use change on water flux; and 3) determine the impacts of climate change scenarios on the water flux of the upper Mara River. This study found that land use change scenarios resulted in more erratic discharge while climate change scenarios had a more predictable impact on the discharge and water balance components. The model results showed the flow was more sensitive to the rainfall changes than land use changes but land use changes reduce dry season flows which is a major problem in the basin. Deforestation increased the peak flows which translated to increased sediment loading in the Mara River.

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Study of batch profile evolution and scouring effect due to the wave and current impacts in the coastal zone has been one of the most important issues in coastal engineering research projects during the past decades .to construct the coastal protective structures such piers, breakwaters and seawalls, it is necessary to estimate the scouring depth and bed level changes in the vicinity of such structures. Furthermore, the time - dependent changes in the equilibrium profile of the surf zone can be of great importance in designing coastal structures. Because of the importance of coastal engineering study in Iran due to the existence of two important coastal area located in the north and south parts of the country, and due to the lack of classified data in this respect (particularly the effect of sea level rise on coastal morphology) in the present study, based on the available data of Bandar Anzali region, an analysis of the coastal zone behavior is made. Bed level elevations are measured and compared with the theoretical equilibrium profile. It is shown that the behavior of the coastal zone in the region is consistent with the dean (equilibrium profile . In the next stage, following extensive investigations, the bed level changes due to a rise in sea level at different locations in the surf zone are estimated. Finally based on the results obtained for profile evolution due to sea level rise, the conclusion is made for design of coastal structures located in the study area. The results obtained from the present study indicate that the sea level rise can have a significant effect on beach profile and resulting erosion in the study area. The results are graphically presented with can be used for design purposes and establishing a data base for the coastal zone in the study region. It is believed that the present work can be regarded as a contribution to the existing knowledge of coast process in the study area and referred to as a basis for the future coastal research projects.

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In this study, consider to the mechanism of controlled depletion paint, has been made the Antifouling (A/F) paints that use these in a paint system which applied on the steel. As a first step, it is necessary to prove that the system subject to investigation does fit into the mechanisms proposed for the CDPs system. According to this, the machine was designed and built as for ASTM D5108-90, D4939-89. Specimens immersed in natural sea water and were rotating by 60 r/min rotor. Painted specimens were tested for 59 days. The main objective of this study was to investigate if new antifouling paint are less toxic than traditional paint and more efficient. For this reason, Zineb and Ziram which is an ingredient in antifouling paints, was also studied. Zineb and Ziram are known as booster biocides in A/P composition. We used the Zineb and Ziram and synthesis of these in a A/F paints. The concentration of booster biocides are 3% and 6% in paints. We use scanning electron microscopy (SEM) for evaluation of paint film. The settlement and the growth of living organism on immersed surfaces was observed during 59 days. According to reports, the growth of organism was observed for A/F paint contains, 3% Zineb after 20days,3%Ziram after 24days and 3% Zineb +Ziram after 30days. By measuring leached rate of the Zn in A/F paints, we figured out the effectiveness of booster biocides on the growth of organism, for example in the absence of booster biocides, the critical released rate for preventing biofilm for A/F paint with ZnO is 15 μg/cm2day. This despite the fact that this figure for A/F paint contain Zineb is 4 μg/cm2, Ziram is 3 μg/cm2 and Zineb +Ziram is 2 μg/cm2.

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A systematic study of the interactions between water and alkyl methyl imidazolium chloride ionic liquids at 298.2 K, based on activity coefficients estimated from water activity measurements in the entire solubility range, is presented. The results show that the activity coefficients of water in the studied ILs are controlled by the hydrophilicity of the cation and the cation-anion interaction. To achieve a deeper understanding on the interactions between water and the ILs, COSMO-RS and FTIR spectroscopy were also applied. COSMO-RS was used to predict the activity coefficient of water in the studied ionic liquids along with the excess enthalpies, suggesting the formation of complexes between three molecules of water and one IL molecule. On the basis of quantum-chemical calculations, it is found that cation-anion interaction plays an important role upon the ability of the IL anion to interact with water. The changes in the peak positions/band areas of OH vibrational modes of water as a function of IL concentration were investigated, and the impact of the cation on the hydrogen-bonding network of water is identified and discussed.

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Résumé : Les ions hydronium (H3O + ) sont formés, à temps courts, dans les grappes ou le long des trajectoires de la radiolyse de l'eau par des rayonnements ionisants à faible transfert d’énergie linéaire (TEL) ou à TEL élevé. Cette formation in situ de H3O + rend la région des grappes/trajectoires du rayonnement temporairement plus acide que le milieu environnant. Bien que des preuves expérimentales de l’acidité d’une grappe aient déjà été signalées, il n'y a que des informations fragmentaires quant à son ampleur et sa dépendance en temps. Dans ce travail, nous déterminons les concentrations en H3O + et les valeurs de pH correspondantes en fonction du temps à partir des rendements de H3O + calculés à l’aide de simulations Monte Carlo de la chimie intervenant dans les trajectoires. Quatre ions incidents de différents TEL ont été sélectionnés et deux modèles de grappe/trajectoire ont été utilisés : 1) un modèle de grappe isolée "sphérique" (faible TEL) et 2) un modèle de trajectoire "cylindrique" (TEL élevé). Dans tous les cas étudiés, un effet de pH acide brusque transitoire, que nous appelons un effet de "pic acide", est observé immédiatement après l’irradiation. Cet effet ne semble pas avoir été exploré dans l'eau ou un milieu cellulaire soumis à un rayonnement ionisant, en particulier à haut TEL. À cet égard, ce travail soulève des questions sur les implications possibles de cet effet en radiobiologie, dont certaines sont évoquées brièvement. Nos calculs ont ensuite été étendus à l’étude de l'influence de la température, de 25 à 350 °C, sur la formation in situ d’ions H3O + et l’effet de pic acide qui intervient à temps courts lors de la radiolyse de l’eau à faible TEL. Les résultats montrent une augmentation marquée de la réponse de pic acide à hautes températures. Comme de nombreux processus intervenant dans le cœur d’un réacteur nucléaire refroidi à l'eau dépendent de façon critique du pH, la question ici est de savoir si ces fortes variations d’acidité, même si elles sont hautement localisées et transitoires, contribuent à la corrosion et l’endommagement des matériaux.

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Abstract.  This study was aimed to determine the influences of turmeric extract supplementation on water holding capacity, cooking loss, pH value and tenderness of broiler chicken meat Data analysis was subject to completely randomized design 5 treatments namely T0, T1, T2, T3 and T4 containing non-turmeric extract, 100 mg/kgBW/day, 200 mg/kgBW/day, 300 mg/kgBW/day and 400 mg/kgBW/day, respectively. Each unit of experiment administered 3 heads with four replications. The results indicated no effect from turmeric extract supplementation on water holding capacity, cooking loss, pH value and tenderness of broiler chicken meat. The average treatments of T0, T1, T2, T3, T4 had water holding capacities of  39.86, 37.58, 36.41, 36.94, respectively; cooking losses of 26.00, 27.58, 27.57, 27.11, and 27.49%, respectively; tenderness of 1.97, 1.95, 1.63, 1.77 and 1.99 Nmm, respectively, and final Body weights of 1,618.5, 1,568, 1,692.5, 1,651.75 and 1,462 g/head, respectively. However, a highly significant influence was observed on the pH values of 6.46, 6.04, 6.21, 6.08 and 5.98. The results indicated that none of the turmeric extract supplementation increased water holding capacity, cooking losses, tenderness and body weight. Key words: broiler, cooking loss, pH values, tenderness, water holding capacity, turmeric Abstrak. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian ekstrak kunyit terhadap daya ikat air, susut masak, nilai pH dan keempukan daging ayam broiler. Manfaat penelitian yaitu tersedianya informasi ilmiah tentang ekstrak kunyit terhadap danging ayam broiler. Perlakuan yang diterapkan adalah T0 tanpa ekstrak kunyit, T1 100, T2 200, T3 300, dan T4 400 mg/kgBB/hari. Data analisis yang digunakan adalah rancangan acak lengkap yang terdiri dari 5 perlakuan dan 4 replikasi. Setiap unit percobaan terdiri dari 3 ekor. Hasil penelitian menunjukkan tidak ada pengaruh pemberian ekstrak kunyit terhadap daya ikat air, susut masak, dan keempukan daging ayam broiler. Rataan untuk perlakuan T0, T1, T2, T3, T4 pada Daya Ikat Air masing–masing 39,86; 37,58; 36,41; 36,94; 34,78%; susut masak 26,00; 27,58; 27,57; 27,11; 27,49%, keempukan 1,97; 1,95; 1,63; 1,77; 1,99 Nmm, dan bobot badan akhir 1.618,5; 1.568; 1.692,5; 1.651,75; 1.462g/ekor. Namun, memberikan pengaruh sangat nyata pada nilai pH 6,46; 6,04; 6,21; 6,08; 5,98. Hasil  menunjukkan bahwa pemberian ekstrak kunyit  tidak meningkatkan daya ikat air, susut masak, keempukan dan bobot badan. Kata Kunci : Broiler, Susut Masak, pH, Keempukan, Daya Ikat Air, Kunyit

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This experiment was study of the enzyme and  probiotic in drinking water mixture was affected on body weight, feed conversion and production index in broiler. This experiment was carried out using 144 broilers, started at one day old and finished at 42 days of age, divided into 4 type treatment of three different level of protein. Experimental method was based on randomized complete design with twelve treatments, if differently, followed by orthogonal  polynomial. Type 1 (unit ABC) was treated with mixture of drinking water and amylase, protease and probiotic at day 3rd through 5th, day 14th , day 21st, day 28th and 35th ;  type 2 (unit DEF) was treated at day 7th ,17th, 27th and 37th ; type 3 (unit GHI) was treated day 21th , day 28th and 35th ; type 4 (unit JKL) without treatment (control). The level of protein for group I of unit ADGJ was 19% of starter feed and 16% of finisher feed. The level of protein for group II  unit BEHK was 21 %of starter feed and 18% finisher feed. The variable used in body weight, feed conversion, production index at the 5th and 6th weeks of age. Result indicated that the body weight optimum was 1483.33 gram at the 5th weeks of age and 1868,89 gram, feed conversion 1, 826 and production index 279,31 at the 6th weeks of age. These findings were observed in the group of chicken given drinking, water amylase, protease and probiotic mixed with at day 3rd trough 5th , day 14th , day 21st , day 28th and day 35th ; The level of protein was 23% of starter feed and 21% of finisher feed. The mixture of enzyme and probiotic in drinking water was concluded to improve in body weight, feed conversion and production index of broiler. (Animal Production 3(1): 26-30 (2001)Key Words: Broiler, enzyme, probiotic,  body weight, feed conversion, production index.

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The effect of mechanochemical activation upon the intercalation of formamide into a high-defect kaolinite has been studied using a combination of X-ray diffraction, thermal analysis, and DRIFT spectroscopy. X-ray diffraction shows that the intensity of the d(001) spacing decreases with grinding time and that the intercalated high-defect kaolinite expands to 10.2 A. The intensity of the peak of the expanded phase of the formamide-intercalated kaolinite decreases with grinding time. Thermal analysis reveals that the evolution temperature of the adsorbed formamide and loss of the inserting molecule increases with increased grinding time. The temperature of the dehydroxylation of the formamide-intercalated high-defect kaolinite decreases from 495 to 470oC with mechanochemical activation. Changes in the surface structure of the mechanochemically activated formamide-intercalated high-defect kaolinite were followed by DRIFT spectroscopy. Fundamentally the intensity of the high-defect kaolinite hydroxyl stretching bands decreases exponentially with grinding time and simultaneously the intensity of the bands attributed to the OH stretching vibrations of water increased. It is proposed that the mechanochemical activation of the high-defect kaolinite caused the conversion of the hydroxyls to water which coordinates the kaolinite surface. Significant changes in the infrared bands assigned to the hydroxyl deformation and amide stretching and bending modes were observed. The intensity decrease of these bands was exponentially related to the grinding time. The position of the amide C&unknown;O vibrational mode was found to be sensitive to grinding time. The effect of mechanochemical activation of the high-defect kaolinite reduces the capacity of the kaolinite to be intercalated with formamide.