bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capillary gas chromatography analysis of Ethiopian mustard to determine variability of fatty acid composition
Authors: Genet Tsige , Labuschagne Maryke T , Hugo Arno 
Published: August 2004

AbstractEthiopian mustard (Brassica carinata A. Braun) is an oil crop grown in Ethiopia. However, the oil is considered low quality, as it contains long chain monounsaturated fatty acids, mainly erucic acid. High erucic acid content is beneficial for the polymer industry, whereas low erucic acid is recommended for food purposes. Both linoleic and linolenic acids are essential fatty acids; however, less than 3% linolenic acid is preferred for oil stability. The objectives of this study were to determine fatty acid composition of Ethiopian mustard to determine the range of genetic diversity for these traits. The genotypes were analysed by capillary gas chromatography (CGC). Twenty‐six fatty acids were identified. In all accessions, the predominant fatty acids were erucic, linoleic, α‐linolenic and oleic, followed by gadoleic and palmitic. To a lesser extent stearic, vaccinic, nervonic and behenic acids were found in all accessions. Significant correlations were found between palmitic acid and stearic acid (positive), between erucic acid and palmitic, stearic, vaccinic, oleic, linoleic and α‐linolenic acids (negative) and eicosenoic acid (positive). Selection and hybridization techniques can be applied to modify the oil content of Ethiopian mustard, considering the variability observed. Copyright © 2004 Society of Chemical Industry
Modification of pasting properties of wheat starch by cyclodextrin glycosyltransferase
Authors: Gujral Hardeep Singh , Rosell Cristina M 
Published: August 2004

AbstractThe effect of cyclodextrin glycosyltransferase (CGTase) on wheat starch functionality was assessed by determining the pasting properties and the dynamic rheology. The addition of CGTase lowered the peak and final viscosity, increased breakdown and markedly decreased the total setback. The influence of CGTase on the ability of starch to form complex with lipids was explored in the presence of fatty acids (stearic and lauric) and an emulsifier (diacetyl tartaric acid ester of monoglyceride, DATEM). Further information about the effect of CGTase on the pasting properties of wheat starch was obtained by analysing the first derivative of the viscograph curves. The cyclodextrins formed in the starch as a result of the cyclization activity of the CGTase were quantified and it was observed that α‐cyclodextrin occurred in the highest concentration followed by β‐ and γ‐cyclodextrins. The starch obtained with CGTase after pasting exhibited better emulsifying properties as it contained the cyclodextrins. The CGTase treatment also modified the dynamic rheology of the starch slurry leading to a decrease in the elastic and viscous modulus. Copyright © 2004 Society of Chemical Industry
Mineral contents and distribution between the soluble and the micellar phases in calcium‐enriched UHT milks
Authors: de la Fuente Miguel Angel , Belloque Josefina , Juárez Manuela 
Published: August 2004

AbstractA study concerning the content of mineral elements (calcium, magnesium, sodium, potassium and phosphorus) and the distribution between the soluble and the micellar phases has been carried out on mineral—mainly calcium—enriched UHT milks. Total calcium contents were 1371–1793 mg l−1 in the 10 brands examined. Percentages of calcium in the soluble phase varied from 23.6 to 37.2%, whereas ionic calcium concentrations found were within a very wide range (44–91 mg l−1). The different forms of phosphorus were studied by 31P‐NMR. Spectra indicated that the majority of the brands employed polyphosphates as stabilizers. Ingredients used to fortify these products consisted of dairy fractions and calcium salts. The modifications in salt balance as consequence of these practices are discussed. Copyright © 2004 Society of Chemical Industry
Pectic polysaccharides of mango (Mangifera indica L): structural studies
Authors: Prasanna Vasu , Prabha Tyakal N , Tharanathan Rudrapatnam N 
Published: August 2004

AbstractPectic polymers of raw and ripe mango fruits revealed several distinct fractions upon diethylaminoethyl‐cellulose chromatography. Fraction I, the arabinogalactan, had a relative ratio of 3:1 for galactose and arabinose, while the two rhamnogalacturonans (fractions II and III) were composed of galacturonic acid, arabinose, galactose and rhamnose in the relative ratios of 69:15:14:2 and 62:10:23:4, respectively. Specific rotation, FTIR, GC‐MS and NMR data revealed fraction I to be a 1→5‐α‐L arabinofuranan linked to the main chain of 1→4‐β‐D‐galactopyranan through 1→3 linkages. The carboxyl‐reduced fraction II had 1→4‐α‐D galactopyranuronic acid residues in the main chain, which were further involved in branching through rhamnose. The striking drop in their abundance and Mr at the end of ripening, denoting depolymerization in situ, is discussed in the context of textural softening. Copyright © 2004 Society of Chemical Industry
Effect of high‐pressure treatments on mechanical and functional properties of restructured products from arrowtooth flounder (Atheresthes stomias)
Authors: Uresti Rocío M , Velazquez Gonzalo , Ramírez José A , Vázquez Manuel , Torres J Antonio 
Published: August 2004

AbstractRestructured fish products from arrowtooth flounder (Atheresthes stomias), an abundant and subutilized species from the Gulf of Alaska, were obtained by hydrostatic pressure processing (HPP) at 400 and 600 MPa with 0–5 min pressure‐holding time. Minced fish meat was massaged with 20 g kg−1 salt at 10 °C during 5 min, stuffed in commercial sausage case and HPP‐treated. Raw and cooked (90 °C for 15 min) pressure‐treated gels were characterized by changes in mechanical properties (texture profile analysis and punch test), protein solubility, electrophoretic profile, expressible water and color. The mechanical properties of raw fish gels increased with pressure level and pressure‐holding time while solubility decreased. Myosin aggregation shown by SDS‐PAGE was associated with changes in mechanical and functional properties. The values for mechanical properties of heat‐induced gels were higher in cooked pressure‐treated samples than in the heat‐only control. Copyright © 2004 Society of Chemical Industry
Seasonal changes in olive fruit characteristics and oil accumulation during ripening process
Authors: Beltrán Gabriel , del Río Carmen , Sánchez Sebastián , Martínez Leopoldo 
Published: August 2004

AbstractOlive fruits of three of the most important Spanish and Italian cultivars, ‘Picual’, ‘Hojiblanca’ and ‘Frantoio’, were harvested at bi‐weekly periods during three crop seasons to study their development and ripening process. Fresh and dry weights and ripening index were determined for fruit, while dry matter, oil and moisture contents were determined in both fruit and pulp (flesh). Fruit growth rate and oil accumulation were calculated. Each olive cultivar showed a different ripening pattern, ‘Hojiblanca’ being the last one to maturate. Fruit weight increased, decreasing its growth rate from the middle of November. Dry matter and moisture contents decreased during ripening in pulp and fruit, ‘Hojiblanca’ showing the highest values for both. Oil content, when expressed on a fresh weight basis, increased in all cultivars, although for the last time period showed variations due to climatic conditions. During ripening, oil content on a dry weight basis increased in fruit, but oil biosynthesis in flesh ceased from November. Olive fruits presented lower oil and higher dry matter contents in the year of lowest rainfall. Therefore fruit harvesting should be carried out from the middle of November in order to obtain the highest oil yield and avoid natural fruit drop. Copyright © 2004 Society of Chemical Industry
Different postharvest dehydration rates affect quality characteristics and volatile compounds of Malvasia, Trebbiano and Sangiovese grapes for wine production
Authors: Bellincontro Andrea , De Santis Diana , Botondi Rinaldo , Villa Ivano , Mencarelli Fabio 
Published: August 2004

AbstractExperiments were carried out using an innovative technology for dehydration based on the passage of air through a tunnel. It was possible to study the postharvest behaviour, at different rates of dehydration, of Malvasia, Trebbiano and Sangiovese grapes. Malvasia and Trebbiano grapes were picked with 17.5% SSC (soluble solids content), while Sangiovese grapes were harvested fully ripe with 26% SSC. All the grapes, in different experiments, were placed in the tunnel with an air speed of 1–1.5 m s−1, 42% RH (relative humidity) and a temperature of 21 °C. After 18 days the weight loss was 50 and 34% respectively in tunnel‐treated Malvasia and Trebbiano grapes, while it was only 13–14% in control grapes (outside the tunnel: RH around 65% and temperature about 20 °C without ventilation). The SSC rose to 35 and 27% respectively in tunnel‐treated Malvasia and Trebbiano grapes compared with 23 and 21% respectively in control grapes. In the case of Sangiovese grapes, after 7 days (the end of treatment) the weight loss was 20.5% in tunnel‐treated grapes and 10.5% in control grapes. The SSC rose to 32% and the acidity increased from 4.8 to 5.8 g l−1in tunnel‐treated grapes compared with 29% and 5 g l−1respectively in control grapes. Total phenols and anthocyanins almost doubled in tunnel‐treated Sangiovese berries. Volatile compound analysis revealed a higher ethanol concentration in all tunnel‐treated grapes but a lower concentration of ethyl acetate and acetic acid. Copyright © 2004 Society of Chemical Industry
Combined use of UV‐C irradiation and heat treatment to improve postharvest life of strawberry fruit
Authors: Pan Jerónimo , Vicente Ariel R , Martínez Gustavo A , Chaves Alicia R , Civello Pedro M 
Published: August 2004

AbstractThe effects of UV‐C (4.1 kJ m−2) and heat treatment (45 °C, 3 h in air) either separately or combined on the quality of strawberries (Fragaria × ananassa cv Seascape) at the 75 or 50% surface red ripening stage were assessed, the latter stage being used only in the firmness test. In addition, the development of surface fungal infections was followed and in vitro germination assays on conidia of Botrytis cinerea and Rhizopus stolonifer performed. Both heat and combined treatments, decreased hue and delayed changes of the L* parameter. All treatments reduced the accumulation of anthocyanins. Control fruit softened most while fruit treated by the combined method were the firmest. The combined treatment reduced fungal infections and delayed in vitro germination of Botrytis cinerea conidia. After 2 days at 20 °C, treated fruit had lower amount of phenolics than the control. Neither the heat nor UV‐C irradiation modified the total sugar content, although the combined treatment decreased it slightly relative to the control. Titratable acidity increased through storage at 20 °C in all fruit, but no differences between control and treated fruit were detected. The combination of UV‐C and heat treatments enhanced the benefits of applying each treatment separately, and could be useful to improve and extend strawberry fruit postharvest life. Copyright © 2004 Society of Chemical Industry
The hydroxyl radical reaction rate constant and products of 3,5‐dimethyl‐1‐hexyn‐3‐ol
Authors: Wells J. R. 
Published: August 2004

AbstractA bimolecular rate constant,kDHO, of (29 ± 9) × 10−12 cm3 molecule−1 s−1 was measured using the relative rate technique for the reaction of the hydroxyl radical (OH) with 3,5‐dimethyl‐1‐hexyn‐3‐ol (DHO, HCCC(OH)(CH3)CH2CH(CH3)2) at (297 ± 3) K and 1 atm total pressure. To more clearly define DHO's indoor environment degradation mechanism, the products of the DHO + OH reaction were also investigated. The positively identified DHO/OH reaction products were acetone ((CH3)2CO), 3‐butyne‐2‐one (3B2O, HCCC(O)(CH3)), 2‐methyl‐propanal (2MP, H(O)CCH(CH3)2), 4‐methyl‐2‐pentanone (MIBK, CH3C(O)CH2CH(CH3)2), ethanedial (GLY, HC(O)C(O)H), 2‐oxopropanal (MGLY, CH3C(O)C(O)H), and 2,3‐butanedione (23BD, CH3C(O)C(O)CH3). The yields of 3B2O and MIBK from the DHO/OH reaction were (8.4 ± 0.3) and (26 ± 2)%, respectively. The use of derivatizing agents O‐(2,3,4,5,6‐pentalfluorobenzyl)hydroxylamine (PFBHA) and N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible DHO/OH reaction mechanisms based on previously published volatile organic compound/OH gas‐phase reaction mechanisms. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 534–544, 2004
Cocatalysis by ruthenium(III) in hydrogen ions catalyzed oxidation of iodide ions: A kinetic study
Authors: Tandon Praveen K. , Mehrotra Alka , Singh Alok K. , Baboo Ramesh , Dwivedi Priy B. 
Published: August 2004

AbstractRuCl3 further catalyzes the oxidation of iodide ion by K3Fe(CN)6, already catalyzed by hydrogen ions. The rate of reaction, when catalyzed only by hydrogen ions, was separated graphically from the rate when both Ru(III) and H+ ions catalyzed the reaction. Reactions studied separately in the presence as well as absence of RuCl3 under similar conditions were found to follow second‐order kinetics with respect to [I−], while the rate showed direct proportionality with respect to [Fe(CN)6]3−, [RuCl3], and [H+]. External addition of [Fe(CN)6]4− ions retards the reaction velocity, while changing the ionic strength of the medium has no effect on the rate. With the help of the intercept of the catalyst graph, the extent of the reaction that takes place without adding Ru(III) was calculated and it was in accordance with the values obtained from the reaction in which only H+ ions catalyzed the reaction. It is proposed that ruthenium forms a complex, which slowly disproportionates into the rate‐determining step. Arrhenius parameters at four different temperatures were also calculated. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 545–553, 2004
Influence of aqueous phase on electrochemical biocorrosion tests in diesel/water systems
Authors: Bento F. M. , Englert G. E. , Gaylarde C. C. , Muller I. L. 
Published: August 2004

AbstractStorage tanks containing microbially contaminated diesel oil are susceptible to corrosion. This process may be evaluated electrochemically in the laboratory using simulated storage systems containing diesel oil and an aqueous phase. The simulated aqueous phase must supply mineral nutrients for microbial growth, together with adequate electrical conductivity, without, however, being too corrosive, so as to allow the aggressive nature of the microbial metabolites to be detected. In this investigation, microbial growth was measured in six electrically conductive media overlaid with metropolitan diesel oil containing an additive package. The microorganisms were the filamentous fungi,Hormoconis resinae, Paecilomyces variotiiandAspergillus fumigatus, the bacteriumBacillus subtilisand the yeastCandida silvicola, all previously isolated from contaminated diesel oil. After 60 days incubation with pure or mixed inocula of these microorganisms, pH, conductivity and viable microorganisms were measured. The electrochemical behaviour of carbon steel ASTM 283‐93‐C was determined in each of the six media (uninoculated) and in selected inoculated medium via measurements of open circuit potential and potentiostatic polarization curves. The uptake of phosphate (corrosion inhibitor), microbial growth, pH, conductivity and anodic and cathodic polarization curves were assessed in the water phase after 30 and 60 days of incubation with each single speciesAspergillus fumigatusandHormoconis resinaeand with the consortium. The medium which proved most appropriate was Bushnell‐Haas medium modified by the omission of chlorides, which allowed satisfactory microbial growth and had low aggressivity towards the steel. The performance of electrochemical tests in aerated, rather than deaerated, electrolyte solutions is suggested to be important to allow the detection of microbial influence on passive film formation and stability.
Corrosion behaviour of zirconium electrode in sodium azide electrolyte as compared to the alkali halide solutions
Authors: Ghoneim A. A. 
Published: August 2004

AbstractThe kinetics of open circuit growth of an oxide film on zirconium electrode in NaN3 solution of various concentrations was investigated using potential and capacitance measurements. The protective oxide film formed in azide solutions was found to thicken with time in two steps, the rate of oxide growth was found to decrease as the azide concentration increased. The corrosion behaviour of the electrode was characterized by ac impedance measurements to obtain detailed information about the effect of azide ion concentration on the electrical properties of the Zr electrode surface. The impedance response for the metal‐metal oxide‐electrolyte system was modeled with a transfer function. The potentiodynamic oxidation of Zr was also studied as a function of the azide ion concentration. The polarization curves showed the peak‐shaped active‐to‐passive transition and the corrosion rate was found to increase with increase of azide ion concentration. The activation energy of corrosion was calculated according to Arrhenius plot and found to be 14.5 kJ mol−1. The polarization results in azide solutions were compared to those obtained in solutions of different halide ions, namely, F−, Cl−, Br− and I− ions. The rate of corrosion was found to decrease in the order Br− > Cl− > F−, I− > azide. Opposite to the behaviour in azide solutions, the halide ions do not show the active‐passive transition.
The wet corrosion of molybdenum thin film –. Part I: Behavior at 25°C
Authors: De Rosa L. , Tomachuk C. R. , Springer J. , Mitton D. B. , Saiello S. , Bellucci F. 
Published: August 2004

AbstractThe corrosion and passivation behaviour of molybdenum thin films obtained by Physical Vapor Deposition (PVD) was investigated in aerated chloride and sulfate solutions at different pH values. Open circuit potential (ocp) measurements, polarisation experiments and electrochemical impedance spectroscopy (EIS) were employed. The experimental results suggest that the metal surface is covered by a passive film; however, corrosion still occurs. For the samples assessed during the current research, the acidic electrolytes tended to be less corrosive; however, a limited passive region was associated with the most basic sulfate or chloride solution. The effect of the pH was found to be more pronounced than the effect of the ion (chloride or sulfate).
Polylactones, 68
Authors: Kricheldorf Hans R. , Ahrensdorf Kirsten , Rost Simon 
Published: August 2004

AbstractFull Paper: Using Sn(II)2‐ethylhexanoate (SnOct2) in combination with 1,4‐butanediol, 1,1,1‐tris(hydroxymethyl)propane (THMP) or pentaerythritol as initiator systems telechelic polyesters or star‐shaped homopolyesters of ε‐caprolactone (ε‐CL) or L,L‐lactide (L‐LA) were prepared. These homopolymers were characterized by solution viscosities, 1H NMR and MALDI‐TOF mass spectra. Using preformed homopolymers as coinitiators star‐shaped polymers having two‐block star arms were obtained. Polymerizations of equimolar mixtures of two monomers yielded star‐shaped polymers with random copolyesters as star arms. The blockiness or randomness of the star arms was characterized by 13C NMR spectroscopy. Homo‐ and copolymerizations of trimethylene carbonate (TMC) were also studied, but they were plagued by intensive side reactions such as formation of cyclic oligomers, coinitiation with water and crosslinking via transesterification.Star‐shaped polymers having two‐block star arms obtained in this study.magnified imageStar‐shaped polymers having two‐block star arms obtained in this study.
Photoactive Azobenzene Polymers Containing Carbazole Chromophores
Authors: Altomare Angelina , Ciardelli Francesco , Mellini Linda , Solaro Roberto 
Published: August 2004

AbstractSummary: Polymeric systems containing side‐chain photoactive chromophores were prepared by free‐radical copolymerization of N‐vinylcarbazole with 4‐methacryloyloxyazobenzene and 4‐methacryloyloxy‐4′‐cyanoazobenzene. The resulting materials were characterized by size exclusion chromatography, TGA and DSC thermal analysis, FT‐IR, 1H NMR, UV‐vis, and fluorescence spectroscopy and photoisomerization experiments. In all cases, the copolymer composition was almost independent of the feed composition, in agreement with the strong tendency of the investigated monomers to alternating copolymerization. Spectroscopic and thermal data clearly highlighted the occurrence of charge‐transfer electronic interactions between electron‐rich carbazole rings and electron‐poor azobenzene chromophores. These interactions facilitate the trans‐cis photoisomerization of azobenzene side‐chains.Aromatic proton NMR spectra of different poly(MCA‐co‐NVK) samples.magnified imageAromatic proton NMR spectra of different poly(MCA‐co‐NVK) samples.
Phenolic Thermoset Matrix Reinforced with Sugar Cane Bagasse Fibers: Attempt to Develop a New Fiber Surface Chemical Modification Involving Formation of Quinones Followed by Reaction with Furfuryl Alcohol
Authors: Trindade Wanderson G. , Hoareau William , Razera Ilce A. T. , Ruggiero Reinaldo , Frollini Elisabete , Castellan Alain 
Published: August 2004

AbstractSummary: A new chemical modification of sugar cane bagasse fibers for phenolic thermoset composites is presented. It consists in creating quinones in the lignin portions of fiber and react them with furfuryl alcohol to create a coating around the fiber more compatible with the phenolic resins used to prepare polymeric matrix. Sodium periodate was used in suitable conditions to oxidize mainly phenolic syringyl and guaiacyl units of the lignin polymer to create quinones, which were characterized by UV‐visible diffuse reflectance spectroscopy by comparison with model compounds. The reactivity of furfuryl alcohol (FA) with fibers was greatly enhanced after they were oxidized: 13% weight percent gain compared to 2% without oxidation. Chemical analysis of unmodified and FA‐modified fibers have shown an important degradation of hemicelluloses and a slight one of cellulose which almost maintains its crystallinity. A 25% decrease of strength and length properties of the fibers after FA chemical treatment was measured by dynamic mechanical analysis. The lignin‐like proportion of the fiber was greatly enhanced after the FA‐treatment. This was confirmed by thermal analysis, DSC, and TGA experiments, on unmodified and FA‐modified fibers. SEM analysis of the fibers and of phenolic composites with modified fibers have confirmed the FA grafting and shown a better compatibility at the interface between the chemically modified fibers and the phenolic matrix. Nevertheless, the chemical treatment of the fibers decreased the impact strength of the composite, which could be caused by the fiber damage suffered during the chemical modification and for the more intense adhesion at the interface, which in some cases decrease somewhat the impact strength.Cross photomicrography of FA‐modified sugar cane bagasse fiber (600×).magnified imageCross photomicrography of FA‐modified sugar cane bagasse fiber (600×).