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Solid Content (solid + content)
Kinds of Solid Content Selected AbstractsEffect of physico-chemical and molecular mobility parameters on Staphylococcus aureus growthINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2003Elena Vittadini Summary The role played by water activity, ,mobility' and physico-chemical properties of the media in modulating microbial response has been the object of large debate in the scientific community. In this study, Staphylococcus aureus growth parameters (lag phase and cell density at 24 h) in brain heart infusion (BHI) and BHI:NaCl (1:1) were analysed in their correlation with physico-chemical/mobility parameters descriptive of the media [solid content, aw, kinematic viscosity, 17O NMR (R2, Pbw and )]. In these high moisture content, liquid and ,homogeneous' media S.aureus growth related to all the physico-chemical and molecular mobility parameters analysed in a similar manner and it was found to be influenced more significantly by added NaCl than by the physico-chemical and molecular mobility of the media. Staphylococcus aureus growth parameters correlated better with aw (relatively independent of NaCl concentration) than with any other parameter considered in this study. [source] A novel approach to excellent UV protecting cotton fabric with functionalized MWNT containing water vapor permeable PU coatingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2007S. Mondal Abstract This research paper presented a novel approach of developing excellent protection from ultraviolet (UV) radiation of cotton fabrics by means of water vapor permeable (WVP) coatings containing multiwall carbon nanotube (MWNT), a stable and strongly UV absorbing species. The WVP of MWNT containing UV protective coatings of the present development are formed from solution polymer of hydrophilic polyurethane (HPU). MWNTs were dispersed in HPU solution by functionalization of MWNT. The nanotube containing HPU coating shows excellent protection against UV radiation, with only 1 wt % of MWNT (calculated based on solid content of the polymer), a UV Protection Factor (UPF) of 174 and with 2.5 wt % of MWNT a UPF of 421 was obtained, which stated excellent protection (UPF ,50) according to the Australian/New Zealand standards. Scanning electron micrographs of coated fabrics surface showed a film like polymer coating, confirming the fabric surface was successfully coated by polyurethane. The coated fabrics would maintain very good water vapor permeability, hence confirmed the wearing comfort. Room temperature (20,23°C) range soft segment crystal melting of HPU enhances the permeability of coated fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3370,3376, 2007 [source] WATER ABSORPTION, LEACHING and COLOR CHANGES DURING the SOAKING FOR PRODUCTION of SOY-BULGURJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2004MUSTAFA BAYRAM ABSTRACT In this study, the soaking process, which is the first step of soy-bulgur production to develop a new type food product, was investigated. the soaking operation was conducted at 30, 50 and 70C for 120 min and samples were taken from the soybean and soaking water at 10 min intervals. Moisture content and color (L, a, b and YI values) of soybean were measured, as well as soluble solids content and color (L, a, b and YI values) of soaking water during the soaking process. the results were analyzed by using ANOVA and Duncan test. Soaking time and temperature were significantly effective (P < 0.05) on all variables, except the time effect on the YI-value. During the soaking, moisture content, lightness (L) and yellowness (b) increased and, redness (a) and yellowness index (YI) of soybean decreased. Soluble solids content, yellowness and yellowness index increased in contrast to a decrease in the lightness and greenness of the soaking water. As a result, soluble solids content in the soaking water increased, which illustrated the leaching of soluble solids from soybean to water. Color of soybean turned to lights, in contrast to darkening and opaqueness of water during soaking. Results showed that the moisture content, soluble solid content, L, a, b and YI values can be successfully modeled using polynomial equations, which can be used to estimate their changes during the soaking operation. [source] THE INFLUENCE of FIELD STRENGTH, SUGAR and SOLID CONTENT ON ELECTRICAL CONDUCTIVITY of STRAWBERRY PRODUCTSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2003I. CASTRO ABSTRACT The effects of field strength, soluble solids (from 14 to 59.5 °Brix) and particle size (using two size distributions) on electrical conductivity were investigated. Electrical conductivity increased with temperature for all the products and conditions tested following linear or quadratic relations. Electrical conductivity was found to vary greatly between strawberry-based products. an increase of electrical conductivity with field strength was obvious for fresh strawberries and strawberry jelly but not for strawberry pulp, probably due to the presence of texturizing agents. This parameter decreases with the increase of solids and sugar content. For some of the formulations tested (solid content over 20% w/w and over 40 °Brix) a different design of ohmic heater may be necessary because of the low values of electrical conductivity. [source] COMPARISON OF ANOLYTE AND CHLORINATED WATER AS A DISINFECTING DIPPING TREATMENT FOR STORED CARROTSJOURNAL OF FOOD QUALITY, Issue 6 2003TILAHUN SEYOUM WORKNEH Packages of carrots were stored at 1 ± 0.5C and ambient temperature (17.5,31.4C). The anolyte water dipping treatment was found to be as effective as chlorinated solutions in controlling growth of aerobic bacteria, molds, yeasts and coliform bacteria during storage. There were no significant differences (P < 0.05) in microbiological changes on carrots dipped in anolyte water for 5, 10, and 20 min. Exposure of carrots to anolyte water for as short as 5 min can be used effectively to reduce and limit growth of aerobic bacteria, molds, yeasts and coliform bacteria. Losses in firmness and physiological weight were higher in carrots dipped in chlorinated water. Anolyte water treatments had no effect on total soluble solid content, pH value, firmness and the overall visual appearance of carrots. [source] Quality Changes of Highbush Blueberries Fruit Stored in CA with Different CO2 LevelsJOURNAL OF FOOD SCIENCE, Issue 4 2009Carolina Duarte ABSTRACT:, Quality changes of blueberries (Vacccinium corymbosum L. cv Brigitta) were evaluated during CA storage (0 °C) with different concentrations of CO2 (5%, 10%, and 15%) combined with 5% O2, respectively. Atmospheric air (20.9% O2+ 0.03% CO2) was used as control. From samples taken at 0, 24, and 48 d of storage, unmarketable fruits and weight loss were recorded as well as color (h), firmness (g), soluble solid content (%), titratable acidity (% citric acid), ratio, and the monomeric anthocyanin content (ppm). At each sampling time, additional units were kept for 3 d at 10 °C to simulate retail holding conditions. Irrespective of gas concentration, 0.9% of the initial fresh weight was lost after 48 d at 0 °C. CA fruit had better quality than control at the 24 d sampling but due to the high number of unmarketable fruits, this advantage was not observed at 48 d at 0 °C. After 24 d of storage, fruits for CA treatments were more firm and had better color, with higher anthocyanin and acidity levels. Soluble solid content showed no significant differences throughout the cold storage period. Residual effect of CA storage was observed at the retail holding condition yielding better firmness, acidity, and ratio. However, the CO2 level tested increased the number of unmarketable fruit in long-term storage (48 d). Response of "Brigitta" blueberries to the different CO2 levels studied was moderate and could be related to the high storage potential of this cultivar. [source] Ultrasonic processing of suspensions of hematite nanopowder stabilized with sodium polyacrylate,AICHE JOURNAL, Issue 11 2009P. Ding Abstract The effect of power input, solid content, surfactant concentration, and pH on the kinetics of wet deagglomeration of hematite nanopowder in ultrasonic comminution device and on the rheology of resulting suspensions has been investigated and compared with the kinetics of deagglomeration and rheology of the suspensions of goethite nanopowder. It has been found that the main mechanisms are fragmentation and erosion, which leads to bimodal transient size distributions of aggregates. Fragmentation of large aggregates starts after certain delay time but erosion of nanoparticles starts from very beginning of processing. Deaggregation of hematite nanopowder is only possible in the presence of surfactant, but increase of concentration of surfactant above certain critical value does not affect kinetics of deagglomeration. The increase of solid concentration up to 20 w/w% reduces the amount of energy necessary for deagglomeration of unit mass of the powder. Effect of pH on the kinetics of deagglomeration and the morphology/rheology of the resulting suspensions is discussed. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Online estimation and control of polymer quality in a copolymerization reactorAICHE JOURNAL, Issue 5 2002Myung-June Park The validity of an online state estimator for a semi-batch MMA/MA solution copolymerization reactor was established using online densitometer and viscometer. Using the conventional extended Kalman filter (EKF) as the state estimator, the experiment was conducted under both isothermal and nonisothermal conditions for application to the control of copolymer properties. Further analysis was made by using ofline measurement data for the mol fraction of MMA in the remaining monomers and the solid content. The EKF was found to provide a good estimate for the state of the copolymerization system. A model predictive controller was designed and implemented to obtain copolymers with uniform copolymer composition and the desired weight average molecular weight by adopting the feed flow rate of MMA and the reaction temperature as control inputs. The controller was proven effective with a satisfactory performance for the control of polymer properties in the semi-batch copolymerization reactor. [source] Synthesis and characterization of poly(methyl methacrylate)/casein nanoparticles with a well-defined core-shell structureJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2003Junmin Zhu Abstract Well-defined, core-shell poly(methyl methacrylate) (PMMA)/casein nanoparticles, ranging from 80 to 130 nm in diameter, were prepared via a direct graft copolymerization of methyl methacrylate (MMA) from casein. The polymerization was induced by a small amount of alkyl hydroperoxide (ROOH) in water at 80 °C. Free radicals on the amino groups of casein and alkoxy radicals were generated concurrently, which initiated the graft copolymerization and homopolymerization of MMA, respectively. The presence of casein micelles promoted the emulsion polymerization of the monomer and provided particle stability. The conversion and grafting efficiency of the monomer strongly depended on the type of radical initiator, ROOH concentration, casein to MMA ratio, and reaction temperature. The graft copolymers and homopolymer of PMMA were isolated and characterized with Fourier transform infrared spectroscopy and differential scanning calorimetry. The molecular weight determination of both the grafted and homopolymer of PMMA suggested that the graft copolymerization and homopolymerization of MMA proceeded at a similar rate. The transmission electron microscopic image of the nanoparticles clearly showed a well-defined core-shell morphology, where PMMA cores were coated with casein shells. The casein shells were further confirmed with a zeta-potential measurement. Finally, this synthetic method allowed us to prepare PMMA/casein nanoparticles with a solid content of up to 31%. Thus, our new process is commercially viable. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3346,3353, 2003 [source] Effect of preharvest sprays containing calcium, magnesium and titanium on the quality of peaches and nectarines at harvest and during postharvest storageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2004María Serrano Abstract Peach and nectarine trees were foliar sprayed with a formulation containing Ca2+, Mg2+ and Ti4+. Parameters related to fruit quality were evaluated at harvest, after 7,28 days of cold storage and after subsequent ripening for 4 days at 20 °C (shelf life). At harvest, treated fruits from both cultivars had higher weight and pulp firmness than control fruits, while no effect was observed for either colour, total soluble solid content (TSS) and titratable acidity (TA) or the time required to ripen on the tree. During cold storage, lower levels of weight loss, colour evolution, TSS/TA ratio and ethylene production and higher pulp firmness were found in treated peaches and nectarines compared with control fruits. Also, the storability of treated fruits was extended for up to 14 days more than that of control fruits. During ripening at 20 °C after different periods of cold storage, parameters related to ripening evolved faster in control than in treated fruits. Also, the occurrence of the climacteric peak of ethylene production was delayed and its intensity was lower in treated peaches and nectarines than in controls. Copyright © 2004 Society of Chemical Industry [source] Evaluation of heat and oxidative damage during storage of processed tomato products.JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2002Abstract The evolution of heat damage during storage of tomato pulp, puree and paste was studied by accelerated aging tests. Heat damage indices,5-hydroxymethyl-2-furfural (HMF), furosine and colour changes (,E),were evaluated for tomato products stored at 30, 40 and 50,°C for up to 90 days. Furosine and ,E values increased following pseudo-zero-order kinetics, and the higher the solid content of the products, the higher were the rate constant values. HMF formation followed pseudo-first-order kinetics in tomato pulp and pseudo-zero-order kinetics in puree and paste samples. Data show that heat damage reactions in tomato products proceed even at room temperature, and the kinetic model provided can be used to predict changes occurring during shelf-life. © 2002 Society of Chemical Industry [source] Synthesis of High Solid-Content Latex using Alkali-Soluble Resin as Sole SurfactantMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2004Marcelo do Amaral Abstract Summary: A novel polymerization procedure to synthesize latex stabilized by alkali-soluble resin (ASR) is detailed. According to this process, latexes with a high solid content and low viscosity are obtained using a substantially lower amount of ASR when compared with existing techniques. Similar rewet properties were found for the latexes obtained by a standard process and for the one obtained by the process described in this work. Comparison of the particle size distributions obtained by conventional emulsion polymerization (,) and by miniemulsion polymerization (,). [source] Polymerisable Miniemulsions Using Rotor-Stator HomogenisersMACROMOLECULAR REACTION ENGINEERING, Issue 4 2008Ula El-Jaby Abstract The use of a rotor-stator mixer as a homogenisation device to make miniemulsion droplets with industrially pertinent solid contents was investigated. Methyl methacrylate/butyl acrylate (50:50 w/w ratio) miniemulsions with droplet diameters from 2 µm to 300 nm and polydispersity indices from 1.2 to 3.6 were used. Miniemulsions with three different mean droplet diameters (300, 400, 600 nm) were polymerised and the evolution of particle size was observed. When 300 nm droplets were polymerised they yielded particles of similar diameter to the original droplets, whereas particle coalescence of the growing particles with a loss of control over the particle size distribution was observed for the 400 and 600 nm droplets. The influence of costabiliser, agitation speed, solid content, colloidal protectors and surface coverage on the evolution of the droplet size and size distribution as well as on the evolution of the average particle size and its distribution were examined. It was observed that changing the above parameters had no impact on the evolution of the particle size, suggesting we have a very robust miniemulsion system. [source] Preparation of Al(OH)3/PMMA nanocomposites by emulsion polymerizationPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2008S. Y. Park Abstract Al(OH)3/PMMA nanocomposites were prepared by the emulsion polymerization of methyl methacrylate (MMA) in the presence of surface-functionalized Al(OH)3 particles. Nanosized Al(OH)3 particles were previously functionalized with a silane coupling agent, 3-(trimethoxysilyl) propyl methacrylate (, -MPS), which was confirmed by FT-IR and XRF analysis. The average size of seed particles was around 70,nm, and the density of the coupling agent on the particles was calculated to be 8.9,µmol,m,2. The emulsion polymerization was attempted at relatively high solid content of 40,46,wt%. The ratio of the seed particles to MMA had a strong influence on the stability of latex as well as the morphology of composites. Nanocomposites where several PMMA nodules were attached on the surface of Al(OH)3 core were produced with stable latex emulsion when the weight percents of Al(OH)3 to MMA were below 20. In the case of higher ratio of 30%, however, the latexes became unstable with an aggregation, and the product morphology was in the shape of large composite. Thermogravimetric analysis showed an improved thermal stability of PMMA composites with the incorporation of Al(OH)3 nanoparticles. Copyright © 2008 John Wiley & Sons, Ltd. [source] A lab-scale reaction calorimeter for olefin polymerizationTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2010Virginie F. Tisse A reaction calorimeter was built to follow slurry-phase polymerizations of ethylene using different types of supported catalysts. It was shown that heat flow calorimetry, employing a high-gain observer for the evaluation of the initial conditions was an extremely useful tool for the measurement of on-line reaction rates, and a study of the influence of different parameters such as the stirring rate or solid content in real time. It was shown that if one uses solid contents under 30% (volume) then it is not necessary to account for the influence of this quantity on the overall heat transfer coefficient. Un calorimètre de réaction a été construit pour le suivi des polymérisations des phases de suspension de l'éthylène utilisant différents types de catalyseurs adaptés. Il a été démontré que la calorimétrie du flux thermique, utilisant un observateur à gain élevé pour l'évaluation des conditions initiales s'est avérée un outil extrêmement utile pour mesurer les taux de réaction en ligne, et pour l'étude en temps réel de l'influence de différents paramètres tels que la vitesse d'agitation ou le contenu en matière solide. Il a été démontré que si l'on utilise la matière solide en dessous de 30% (en termes de volume), alors il n'est pas nécessaire de prendre en compte l'influence de cette quantité sur le coefficient global de transfert thermique. Can. J. Chem. Eng. © 2010 Canadian Society for Chemical Engineering [source] Production and Properties of Spray-dried Amaranthus Betacyanin PigmentsJOURNAL OF FOOD SCIENCE, Issue 7 2000Y.Z. Cai ABSTRACT: Amaranthus betacyanin extracts were spray-dried using a range of maltodextrins [10-25 dextrose equivalent (DE)] and starches (native/modified) as carrier and coating agents at 5 inlet/outlet air temperatures and 4 feed solid contents. Higher inlet/outlet air temperatures caused greater betacyanin loss during spray drying, and affected slightly the pigment stability during storage. Adding maltodextrins and starches significantly reduced the hygroscopicity of the betacyanin extracts and enhanced storage stability. The 25 DE/10 DE mixed powders provided a longer predicted half-life (63.6 wk) compared to the 25 DE and the 10 DE powders separately. The best dried pigment-containing powder made was superior to commercial red beet powder in physical properties. [source] RHEOLOGY OF MULBERRY PEKMEZJOURNAL OF TEXTURE STUDIES, Issue 5-6 2001A. KAYA The rheological behavior of mulberry pekmez (concentrated mulberry juice, °Brix = 72.0) with different solid contents (62.8, 55.8 and 46.0) was studied over the temperature range of 10, 20, 30, 40, 50 and 60C using a Controlled Stress Rheometer. Mulberry pekmez was found to exhibit Newtonian behavior. The effect of temperature can be described by means of Arrhenius equation. The activation energies for flow of samples vary from 53.11 to 12.73 kJ/mol depending on soluble solid contents. The effect of soluble solids on viscosity can be described by an exponential equation. The best model to describe the combined effects of temperature and soluble solids content on viscosity is ,= 3.40 X 10 -10 exp (0.12C + 3723/T). [source] RHEOLOGICAL PROPERTIES OF HOT PEPPER-SOYBEAN PASTEJOURNAL OF TEXTURE STUDIES, Issue 4 2001B. YOO Rheological properties of fermented hot pepper-soybean paste (HPSP) were evaluated at different total solid contents (TS, 43.6-54.7%) and temperatures (10-40C). HPSP samples at 20C are highly shear thinning fluids (n=0.25-0.33) with large magnitudes of Casson yield stresses (106-573 Pa). Consistency index (K) and apparent viscosity (,a,20) increased with increase in TS. Apparent viscosity of HPSP obeyed the Arrhenius temperature relationship. The magnitudes of activation energy (7.6-20.4 kJ/mole) for HPSP increased with increase in TS. A single equation, combining the effects of temperature and concentration on ,a,20, was used to describe flow behavior of HPSP. The time-dependent model of Weltman was found to be most applicable (R2= 0.97-0.99) for HPSP. Storage (G') and loss (G") moduli increased with increase in TS, while complex viscosity (,*) decreased. Magnitudes of G'were higher than those of G" over the entire range of frequencies (,). [source] Centrifugal Gel Casting: A Combined Process for the Consolidation of Homogenous and Reliable CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2010Saeed Maleksaeedi In this work, a combined process, called centrifugal gel casting (CGC), was proposed for the fabrication of homogenous and reliable monolithic and composite ceramics starting from submicrometer-sized powders. This method exploits the advantages of both conventional gel casting (GC) and centrifugal slip casting (CSC), while overcoming the limitations associated with the two methods. Via this process, a relatively low centrifugal force is applied to form a highly concentrated slurry in the mold cavity, which is then followed by in situ polymerization of slurry during gelation. In this work, concentrated alumina slurries with different solid contents from 45 to 65 vol% were consolidated by the three forming methods mentioned above. Various properties of green and fired products were measured and compared. Shorter processing time, lower centrifugal force, higher green strength, and minimal segregation are observed to be the characteristics of CGC in comparison with CSC. In situ elimination of bubbles with no need for degassing and the ability to remove heterogeneities, on top of high reliability and the potential to process higher viscosity slurries, are the main advantages of this method over the conventional GC. [source] Stabilised cocosoy beverage: physicochemical and sensory propertiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2006Horsfall D Mepba Abstract Beverages formulated from extracts of blanched coconut meat and germinated soybean were compared for their proximate composition to achieve the recommendations for vegetable milks. The stability of cocosoy beverage treated with varying levels (0.2,1.0%, v/v) of a 20% gum acacia solution was determined visually and objectively after 5 days of quiescent refrigerated storage. Cocosoy beverage (50:50, v/v coconut milk to soy milk) had 3.51% protein, 3.53% fat and 5.17% carbohydrate. Similarly, it contained 13.0, 5.2, 14.7, 18.7, 0.5 and 0.3 g kg,1 K, Na, Ca, Mg, Fe and P, respectively. Compared with whole coconut milk and reconstituted whole milk powder, cocosoy beverage had significantly higher total solid contents and viscosity but lower pH and buffer index. A total solids top to bottom (T/B) ratio and protein (T/B ratio) of 0.97 and 1.0, respectively, corresponding to a separation index of 1.0, was obtained in cocosoy beverage stabilised with 1.0% gum acacia. Cocosoy beverage stabilised with 1.0% (v/v) gum acacia was rated significantly higher for all the tested sensory attributes. Cocosoy beverage, similar to whole coconut milk, had high contents of glucose and sucrose, a moderate content of fructose, low content of raffinose and no trace of stachyose. Copyright © 2006 Society of Chemical Industry [source] Metabolic response to two hydrocooling temperatures in sweet cherries cv Lapins and cv SunburstJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2006Rafael Alique Abstract Physiological and metabolic characterisation and analysis of response to two hydrocooling temperatures in cv Sunburst (early season) and cv Lapins (mid-season) cherries during post-harvest life has been studied. Samples were hydrocooled with water at 1 °C to reach 6 °C inside the fruit (HC-6C) and 2 °C (HC-2C) inside the fruit. After harvesting, Sunburst samples presented higher respiration rates and lower malic acid and sorbitol contents than Lapins. Glucose and fructose contents were similar in the two varieties. Sunburst control exhibited a higher respiration rate than Lapins and a higher rate of conversion from sorbitol to fructose. The change of glucose and malic acid consumption over 4 days at 20 °C was similar for the two varieties. Hydrocooling reduced respiration and the consumption of respiratory substrates. The residual effect of hydrocooling was especially significant in cherries of both varieties that had been pre-cooled to 2 °C. Hydrocooling delayed loss of skin and pulp firmness, and reduced loss of titratable acid and soluble solid contents over 4 days at 20 °C in both varieties. Hydrocooling to 2 °C checked loss of quality with respect to controls for both varieties after 4 days at 20 °C. Lapins showed better conservation properties than Sunburst under all the experimental storage conditions. Hydrocooling reduced total losses in both varieties, especially in cherries pre-cooled to 2 °C. Hydrocooling also had several residual effects: reduction of the respiration rate and consumption of respiratory substrates, and slowing of loss of quality, particularly for Lapins. Copyright © 2006 Society of Chemical Industry [source] Polymerisable Miniemulsions Using Rotor-Stator HomogenisersMACROMOLECULAR REACTION ENGINEERING, Issue 4 2008Ula El-Jaby Abstract The use of a rotor-stator mixer as a homogenisation device to make miniemulsion droplets with industrially pertinent solid contents was investigated. Methyl methacrylate/butyl acrylate (50:50 w/w ratio) miniemulsions with droplet diameters from 2 µm to 300 nm and polydispersity indices from 1.2 to 3.6 were used. Miniemulsions with three different mean droplet diameters (300, 400, 600 nm) were polymerised and the evolution of particle size was observed. When 300 nm droplets were polymerised they yielded particles of similar diameter to the original droplets, whereas particle coalescence of the growing particles with a loss of control over the particle size distribution was observed for the 400 and 600 nm droplets. The influence of costabiliser, agitation speed, solid content, colloidal protectors and surface coverage on the evolution of the droplet size and size distribution as well as on the evolution of the average particle size and its distribution were examined. It was observed that changing the above parameters had no impact on the evolution of the particle size, suggesting we have a very robust miniemulsion system. [source] A lab-scale reaction calorimeter for olefin polymerizationTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2010Virginie F. Tisse A reaction calorimeter was built to follow slurry-phase polymerizations of ethylene using different types of supported catalysts. It was shown that heat flow calorimetry, employing a high-gain observer for the evaluation of the initial conditions was an extremely useful tool for the measurement of on-line reaction rates, and a study of the influence of different parameters such as the stirring rate or solid content in real time. It was shown that if one uses solid contents under 30% (volume) then it is not necessary to account for the influence of this quantity on the overall heat transfer coefficient. Un calorimètre de réaction a été construit pour le suivi des polymérisations des phases de suspension de l'éthylène utilisant différents types de catalyseurs adaptés. Il a été démontré que la calorimétrie du flux thermique, utilisant un observateur à gain élevé pour l'évaluation des conditions initiales s'est avérée un outil extrêmement utile pour mesurer les taux de réaction en ligne, et pour l'étude en temps réel de l'influence de différents paramètres tels que la vitesse d'agitation ou le contenu en matière solide. Il a été démontré que si l'on utilise la matière solide en dessous de 30% (en termes de volume), alors il n'est pas nécessaire de prendre en compte l'influence de cette quantité sur le coefficient global de transfert thermique. Can. J. Chem. Eng. © 2010 Canadian Society for Chemical Engineering [source] Comparison of the characteristics of set type yoghurt made from ovine milk of different fat contentINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2007Stelios Kaminarides Summary Characteristics of four types of yoghurt made from ovine milk containing 6.6%, 3.8%, 2.3%, or 0.9% fat respectively were studied. The yoghurt produced from ovine milk with high fat had the highest flavour and texture scores, fat and total solids content and firmness, but the lowest syneresis, lactic acid and galactose content. Low-fat yoghurts can be successfully produced from homogenised ovine milk and these yoghurts did not significantly differ from that of full fat yoghurt in values for ash, lactose, citric acid, pyruvic acid, pH and non-protein nitrogen. The HPLC procedure that was used for the determination of lactose was appropriate for the simultaneous determination of galactose and organic acids in milk or yoghurt. A total of sixteen volatile compounds were identified in ovine yoghurt and the main volatile flavour compounds in yoghurt on 2 days were acetic acid, acetaldehyde, acetone, diacetyl, 2-butanone, 3-hydroxy-2-butanone and 3-methyl-2-butanone. [source] EFFECTS OF VARIETY AND GROWTH SEASON ON THE ORGANOLEPTIC AND NUTRITIONAL QUALITY OF HYDROPONICALLY GROWN TOMATOJOURNAL OF FOOD QUALITY, Issue 1 2006MIKEL ANZA ABSTRACT The effects of variety and season on several organoleptic and nutritional quality parameters (i.e., dry weight (dw), total sugars, soluble solid compounds, titratable acidity (TA), electrical conductivity (EC), juiciness, firmness, vitamin C (vit C), total phenolic compounds, hydrophilic antioxidant capacity and minerals) of five different varieties of tomatoes (i.e., Jack, Cabrales, Jaguar, Iker and Nevada) grown in two crop cycles (spring and autumn) were studied. Each variety presented its own specific characteristics regarding the chosen parameters. Firmness, TA and EC were season dependent, whereas soluble solids content did not change between cycles. In some varieties, the dw, juiciness and total sugars were affected by climatic conditions. The total phenolic compounds and the hydrophilic antioxidant capacity were variety dependent in both cycles. By contrast, the vit C content was variety dependent only in the autumn cycle. Similarly, these latter parameters (phenolic compounds, hydrophilic antioxidant capacity and vit C) were also season dependent, showing higher values in the spring than in the autumn cycle. The effect of tomato variety and season on mineral contents is also discussed. Those tomatoes grown in the spring cycle had better quality according to the organoleptic parameters studied here as well as to a higher antioxidant capacity. The percentages of the recommended dietary allowances supplied by the studied tomatoes were not significantly affected by variety or season, despite differences in their physicochemical compositions. [source] The production of high polymer to surfactant microlatexesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2010Raul P. Moraes Abstract Starved-feed microemulsion polymerization of styrene was investigated. The influence of the type (SDS or Dowfax 2A1) and concentration of anionic surfactant on the final particle size of latex made by the polymerization of microemulsions of styrene was studied. In addition, the influence of 1-pentanol and acrylic acid as cosurfactants was examined. Latexes with 20% solids content and polymer to surfactant ratio of 22 were produced, with a particle diameter of 42 nm and very low polydispersity indexes. Smaller particles are produced using SDS than Dowfax 2A1 for the same weight fraction of surfactant; however, similar particle sizes were obtained with the same molar concentrations of SDS and Dowfax 2A1. Further shot additions of monomer increased solids level as high as 40% and polymer to surfactant ratios greater than 40, with particles remaining monodisperse with average diameter smaller than 60 nm. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 48,54, 2010 [source] Nutrient content and yield in relation to top breakover in onion developed from greenhouse-grown transplants,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009Vincent M Russo Abstract BACKGROUND: Onions (Allium cepa L.) generally are harvested based on percentage of tops broken over. Since plant metabolism changes over time, percentage of tops broken over may be used to determine a harvest time to deliver marketable bulbs with the best nutrient content. RESULTS: The cultivars Candy and Texas Grano 1015 Y were harvested at 10%, 20%, 30%, 40% and 50% breakover in 2006 and 2007. Larger and heavier bulbs were produced by Candy and in 2006, the year with near-normal precipitation. There was little difference in bulb size and weight due to percent breakover. Contents of chemical moieties in bulbs were affected by year, with the majority of values being higher in 2006, and there were either no differences due to cultivar, or where differences were found nitrate-N, phosphate and sulfate contents were lower in Candy. Soluble solids content was lower in 2006 and higher in Candy. Content of nitrogen and phosphorous in a Kjeldahl digest, nitrate-N, phosphate, potassium and sulfate were either linearly or quadratically distributed over percent breakover. Nitrite-N, calcium, magnesium, sodium and soluble solids were randomly distributed over percent breakover. Bulb size and weight did not change from the 20% breakover point, and most of the chemical moieties analyzed, with the exception of nitrate- and nitrite-N values, were highest below the 30% breakover. CONCLUSION: Harvest occurring soon after breakover begins could be beneficial in terms of nutrient content without loss of bulb size or weight. Copyright © 2009 Society of Chemical Industry [source] Effects of organic and conventional production systems on quality and nutritional parameters of processing tomatoesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2009Joy Rickman Pieper Abstract BACKGROUND: The impact of organic and conventional production systems on quality and nutritional parameters of fruits and vegetables is still under discussion. The objective of this study is to determine whether the production system has a significant effect on the quality and nutritional content of one variety of processing tomatoes grown on a commercial scale by comparing three different growers for two production years. RESULTS: Conventional tomatoes appeared to be more mature at time of harvest as determined by visual inspection of color. Total and soluble solids were significantly higher and consistency was greater in organic tomatoes. Differences in nutrient content were not statistically significant between production systems. Glutamate, glutamine, and tyrosine levels were significantly higher in conventional tomatoes, as were total nitrogen and ammonium concentrations. CONCLUSION: Results from this study show that nutritional and quality parameters vary greatly by grower, production system, and year for the same tomato cultivar. Significantly higher average soluble solids content and consistency in organic tomatoes are especially important to the processing tomato industry. The apparent slower development of organic tomatoes may be responsible for many of the significant findings in this study and may explain some of the conflicting reports in previous literature. Copyright © 2008 Society of Chemical Industry [source] Milk yields, physico-chemical properties and composition of milk from indigenous Malawi goats and their Saanen half-bredsINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2003P.P. Mumba Abstract A study to compare milk yield, some physico-chemical properties and the chemical composition of milk from 23 indigenous Malawi goats and 10 Malawi local × Saanen crosses was carried out from January to March 2000. The results showed that the average milk yield from the crosses (102.0 ± 11.21 kg) was higher (P < 0.01) than that from the indigenous goats (37.1 ± 4.79 kg). However, the pH and specific gravity of both milk samples did not differ significantly from each other. The latter was attributed to the fat and total solids contents, which did not differ significantly in the two milk samples. Although the crude protein content was not significantly different, lactose and minerals, namely calcium, sodium, magnesium, potassium and chloride, were higher (P < 0.01) in milk from the crosses than in milk from the indigenous goat. The results have shown that the levels of nutrients in goat milk are high, and this is indicative of its potential to improve the diets of rural Malawians. Also, as smallholder farmers sell raw unheated milk to the processing plants, such milk should not be kept for> 33 h in the cool dry season and for not> 20 h in the hot dry season. Farmers can also adopt a charcoal cooler to save the milk for an even longer time than they can at room temperature. In this case, the raw milk can only be stored for not> 20 h in the cool dry season and not> 16 h in the hot dry season. [source] Microencapsulation by Spray Drying of Multiple Emulsions Containing CarotenoidsJOURNAL OF FOOD SCIENCE, Issue 7 2004M.E. Rodríduez-Huezo ABSTRACT: Water-in-oil-in-water (W1/O/W2) multiple emulsions with 25% and 35% solids contents were spray-dried producing microcapsules with 3.9:1, 2.6:1, and 1.4:1 biopolymers blend to primary emulsion ratios and 0.25% (w/w) theoretical carotenoids concentration. Microcapsules with better morphology, encapsulation efficiency, and larger particle size were those obtained from higher biopolymers blend to primary emulsion ratios and solids content, but showed relatively higher carotenoids degradation kinetics than microcapsules made with lower biopolymers blend to primary emulsion ratios and solids content, which exhibited poorer morphology, encapsulation efficiency, and smaller particle size. Microcapsules stored at different water activities showed maximum carotenoids degradation at a water activity (aw) of 0.628, with lower carotenoids degradation occurring at lower or higher aw. [source] | |||||||||||||||||||||||||