bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beitrag zum enzymatischen Abbau von Stärkeschlichten auf einem Textilgut
Authors: Denter Ulrike , Knittel Dierk , Schollmeyer Eckhard 
Published: November 2006

AbstractEs wurden Untersuchungen zum Einsatz von Cyclodextrin‐Glucosyl‐ Transferase beim enzymatischen Entschlichten von stärkegeschlichtetem Baumwollgewebe durchgeführt. Das verwendete Enzym soll beim Stärkeabbau in Lösung selektiv β‐Cyclodextrin bilden. Wie die vorliegenden Experimente zeigen, ist die CGTase in der Lage, Stärke nicht nur in Lösung, sondern auch auf einem textilen Träger abzubauen. Unter den gegebenen Randbedingungen katalysiert das Enzym die Bildung von α‐Cyclodextrin. Um eine gegenüber α‐Cyclodextrin verstärkte Anreicherung von β‐Cyclodextrin zu erreichen, ist eine genaue Analyse des Prozesses unter Variation und Optimierung der Randbedingungen erforderlich.
Characterization of Hydroxyethyl Starch by Polymer Analysis for Use as a Plasma Volume Expander
Authors: Kulicke Werner‐Michael , Roessner Dierk , Kull Wiebke 
Published: November 2006

AbstractHydroxyethyl starch is currently finding increasing use as a basis material for plasma volume expanders. In clinical applications it is desirable to have a precise knowledge of the steric and chemical structure, as these affect the pharmacokinetics and pharmacology.Characterization involved the determination of the mean molar masses and distribution functions of various hydroxyethyl starches, with molar masses ranging from 40,000 g/mol to 200,000 g/mol and degrees of substitution from 0.38 to 0.64, by means of size exclusion chromatography followed by double detection (MALLS/RI). Hydrodynamic data (Staudinger indices, Huggins constants and equivalent diameters) were determined by viscometric means.The chemical structure of the hydroxyethyl starches were clarified by {1H}‐13C NMR spectroscopy. Signal assignment for the {1H}‐13C NMR spectra made it possible to carry out an absolute determination of the molar, mean and partial degrees of substitution and the degree of branching. The partial degrees of substitution of the carbon atom C‐2 was found to constitute between 60 and 80% of the total degree of substitution. This value is significantly larger than the partial degrees of substitution at the atoms C‐3 and C‐6, which were found to contribute up to approximately 10% and 20% respectively of the total degree of substitution. Degrees of branching ranging from 3.1% to 5.5% were detected.
Amino Derivatives of Starch Part 1: Amination of Amylose Oxidized with Nitrogen Dioxide
Authors: Tihlérik Karol 
Published: November 2006

AbstractAmylose oxidized with nitrogen dioxide, having D.O. by (C=O) 0.38 and by (COOH) 0.94 was converted into its oxime, which after reduction with sodium and isopropyl alcohol yielded (1→4)‐2‐amino‐2‐deoxy‐α‐glucopyranuronan with D.S. by (NH2) 0.30 and by (COONa) 0.85. After acetylation and O‐deacetylation (1→4)‐2‐acetamido‐2‐deoxy‐α‐d‐glucopyranuronan with D.S. by (NHCOCH3) 0.28 and by (COONa) 0.80 was obtained.
Clay as a Carrier in Starch Encapsulated Herbicides Prepared by Extrusion Processing
Authors: Carr Merle E. , Wing Robert E. , Doane William M. 
Published: November 2006

AbstractMetolachlor and atrazine herbicides were separately incorporated into matrices containing all starch, all clay, and starch/clay blends by a twin‐screw extrusion process. A low‐cost clay and unmodified corn‐starch were preblended dry, processed with water and herbicide in the extruder at 70–95°C, and extruded at 65% solids using an intense mixing screw. The extrudates were dried, milled, sieved (14‐20 and 20‐40 mesh), and analyzed for level of entrapped herbicide. The effect of various levels of clay and other variables on encapsulation efficiency, swellability, and release rates of the products in water were determined. The study showed that clay in the preblends of up to 50% had rather small effects on encapsulation efficiency and release rates of the products in water. As little as 20% starch in the blends remarkably slowed the release rates compared to that of clay alone. Processing the clay, herbicide and water without starch in the extruder significantly slowed the release rate compared to an unprocessed mixture of clay, metolachlor, and water. In all cases metolachlor was released more quickly than atrazine from the products (10‐27% active ingredient).
Molecular Characteristics of High Amylose Starches
Authors: Praznik Werner , Huber Anton , Watzinger Sabine , Beck Roland H. F. 
Published: November 2006

AbstractA new methodology for the analysis of starch which combines complexation/precipitation‐techniques with size exclusion chromatography and enzymatic debranching is described. Application of this methodology yields detailed information about the microstructure of starch. The non‐branched/long‐chain‐branched glucans (amylose) of wrinkled pea and high amylose corn starch proved to be different in respect to average molecular weight and branching characteristics, whereas close similarity was found for the short‐chain branched components (amylopectin) of the two starches, both of them showing a bimodal molecular weight distribution.
The Catalytic Effect of Bromide in the Hypochlorite Oxidation of Linear Dextrins and Inulin
Authors: Besemer Arie C. , van Bekkum Herman 
Published: November 2006

AbstractThe effect of bromide in the hypochlorite oxidation of amylodextrins (short chain amylose) and inulin on the reaction rate was investigated. It was found both in the linear dextrins and inulin oxidation that the rate increases linearly with the sodium bromide concentration, which proves the catalytic effect of this substance. The origin of the catalysis is the rapid Br−/OCl− conversion. The second‐order rate constant of the reactionCarbohydrate + HOBr/OBr− → polycarboxylates + HBr/Br− was determined at pH 9.0 and 294‐298 K.The activation energy for the oxidation of amylodextrins amounts to 67 kJ.mole−1. The highest rate was found at pH 8.25. The reaction rate is almost independent of pH in the region 8.5–9.5. Because of the simultaneous occurrence of bromine, Br3−. hypobromous acid and hypobromite in the pH region investigated, it is difficult to elucidate the oxidation mechanism.
Technological Evaluation of Nitrogen Containing Starch Derivatives as Sizing Agents
Authors: Hebeish A. , Ragheb A. A. , Refai R. , Saad M. A. , Dokki I. Abd El‐Thalouth 
Published: November 2006

AbstractThe structural changes brought about by introducing different nitrogen containing groups via cyanoethylation, carbamoylethylation and carbamation in the molecules of rice and maize starches and oxidized starches derived thereof and the onset of these changes on the technical properties of yarns sized with such starch products were investigated. It was found that the apparent viscosity of pastes prepared from those products depends on the nature of starch, the degree of oxidation prior to chemical modification, the nature of modification as well as the measuring conditions, i. e. the rate of shear and temperature. Cotton yarns sized using these starch derivatives were measured for yarn number, tensile strength, C.V.%, elongation at break and C.V.% in elongation. Besides, the weavability test expressed as the minimum number of cycles due to abrasion (St1) and average number of cycles due to abrasion (St6) were investigated. A comparison among modified starches prepared from rice starch would reveral that the highest value of St1 is obtained with yarns sized using carbamoylethylated sample derived from unoxidized starch. With maize starch, on the other hand, the highest value of St1 is obtained with cotton yarns sized using carbamoylethylated starch derived from starch oxidized by 1 g/l active chlorine.
Synthesis and Processing of Graft Copolymers from Cornstarch and Methyl Acrylate: Physical and Mechanical Properties
Authors: Patil Damodar R. , Fanta George F. 
Published: November 2006

AbstractStarch‐g‐poly(methyl acrylate) (S‐g‐PMA), containing 40‐65% PMA, was prepared with ceric ammonium nitrate (CAN) initiation in a 2‐gallon reactor. CAN initiator was added either in one portion or portionwise. Graft copolymers were characterized with respect to % acetone‐extractable polymer (largely PMA homopolymer), PMA content of the graft copolymer, and Mw of PMA grafts. Normal cornstarch as well as waxy and high amylose cornstarches were used in the grafting reaction. Conversions of monomer to polymer were nearly quantitative. Continuous plastic ribbons for tensile testing were prepared by extrusion processing. Tensile properties varied with the method used for CAN addition (i. e., single portion vs. portion‐wise) and depended upon the particular starch variety used in the graft polymerization reaction. Since water acts as a plasticizer for starch, samples extruded at high moisture content exhibit higher % elongation (%E) values than the same polymers extruded at low moisture. Values for %E also increase with higher percentages of PMA in the graft copolymer.
Biogenic Amino Acids and their Metal Salts as Catalysts of Caramelization
Authors: Sikora M. , Kraków P. Tomasik 
Published: November 2006

AbstractBasic amino acids and one neutral aminohydroxy acid ‐ serine ‐, all at the concentration of 5%(w/w), are the most suitable as catalysts of caramelization. Among basic amino acids asparagine is the superior catalyst. Although caramels obtained with serine as the catalyst showed higher tinctorial strength they do not fully dissolve in alcohol, beer, hydrochloric acid and aq. citric acid. The application of lithium, sodium, and potassium salts of amino acids under study sometimes give an increase of tinctorial strength of caramels which, however, form precipitate in the citric acid test. The choice between particular salts as catalysts can be dependent on requested aroma of the caramel.
Gelatinization Characteristics of a Cassava/Corn Starch Based Blend during Extrusion Cooking Employing Response Surface Methodology
Authors: Seibel Wilfried , Hu Ruguo 
Published: November 2006

AbstractThe gelatinization characteristics of a cassava/corn starch based blend with relatively high moisture content during cooking extrusion were studied. The study was carried out by using Response Surface Methodology. The results showed that the die temperature Td (°C) was the main influencing factor for the starch gelatinization, and the feed rate of the materials Vf (g/min) was another minor one. Because of the high material moisture content during extrusion the moisture content Mc (%) influenced the gelatinization degree not so obviously. The residence time distribution of the mass during extrusion were studied as well as discussed as a influencing factor on the gelatinization results.
Kinetics of the Formations of Gelatinized and Melted Starch at Extrusion Cooking Conditions
Authors: Qu Di , Wang S. S. 
Published: November 2006

AbstractTypical DSC thermograms of starch phase transition in the low moisture content range (15‐40%) showed two thermal transition peaks. This suggests the existence of two different cooking mechanisms. We call them gelatinization and melting. “Gelatinization” describes thermal transition of starch with water and “melting” without water. Kinetics of the formation of gelatinized starch (GEL) and melted starch (MELT) were studied. Conversions caused by gelatinization and melting were separately analyzed by using information from DSC (Differential Scanning Calorimetry) isothermal studies. The rate of formation of gelatinized fraction followed first order kinetics and that of melted fraction zeroth order. The overall reaction rate followed zeroth order because melting is the dominant mechanism of the two under limited water contents of extrusion cooking conditions.
Investigations on High Amylose Corn Starch Films. Part 1: Wide Angle X‐Ray Scattering (WAXS)
Authors: Bader Herbert G. , Göritz Dietmar 
Published: November 2006

AbstractBy autoclaving aqueous high amylose corn starch suspensions, homogenous and isotrope films were obtained with different processing parameters. The films were used for structural investigations by wide angle x‐ray scattering. The experimental results prove a systematical dependence on different parameters: on one hand the starch crystallinity shows a continous transformation from the ‘B’‐type to the ‘A’‐type with increasing drying temperature, on the other hand the drying temperature also influences the kind of interaction between the starch chains and the native lipids. Fatty acids were added to clearly outline the corresponding effects.
Chemical Composition of Cell Wall Material from Sweet Potato Starch Residue
Authors: Noda Takahiro , Takahata Yasuhiro , Nagata Tadahiro , Shibuya Naoto 
Published: November 2006

AbstractCell wall material was isolated from the residue obtained after the extraction of sweet potato starch by treatment with the α‐amylase. The wall material was fractionated by successive extraction with various reagents. The pectic substance was mainly composed of uronic acid (47.1%) residues and contained galactose as the predominant neutral sugar residues. The hemicellulosic fraction was further fractionated by precipitation with iodine in the presence of calcium chloride to give two fractions, a iodine precipitatable‐iodine complex (HC‐IP) and a supernatant solution (HC‐IS). The HC‐IS fraction had a higher glucose content (53.4%), whereas the HC‐IP fraction had a high content of xylose residues (35.1%). The HC‐IP fraction consisted mainly of xylan, as judged by the degradation with purified xylanase.
Investigations on High Amylose Corn Starch Films. Part 2: Water Vapor Sorption
Authors: Bader Herbert G. , Göritz Dietmar 
Published: November 2006

AbstractBy autoclaving a watery high amylose corn starch suspension, homogenous and isotrope films were obtained with different processing parameters. The films were used for extensive investigations on the water vapor sorption behavior.It was observed that both the internal structure and the native lipid content of the investigated starch effect the sorption behavior. A good theoretical description of the sorption behavior was obtained with a modified B.E.T.‐equation only for films prepared from a previously defatted starch fraction. In addition it was shown by using this modified B.E.T.‐equation that a temperature dependent prediction is possible for the sorption behavior of defatted starch films.
Effects of Suspension Crosslinking Reacting Conditions on the Sizes of Starch Microspheres
Authors: Jiugao Yu , Jie Liu 
Published: November 2006

AbstractUsing the method of suspension crosslinking polymerization and epichlorohydrin as the crosslinking agent, starch microspheres have been synthesized. And the effects of reacting parameters, including the surfactant concentration, stirring speed, two phases viscosities and densities on the microspheres mean size (18–36μm) are also discussed. One equation is deduced to demonstrate these effects:
Corn Starch‐Xanthan Gum Interaction and Its Effect on the Stability During Storage of Frozen Gelatinized Suspension
Authors: Ferrero C. , Martino M. N. , Zaritzky N. E. 
Published: November 2006

AbstractThe knowledge of starch pastes behavior during frozen storage becomes necessary to understand more complex systems (e.g. sauces, dressings and desserts) The effect of sub‐zero storage on the quality attributes of corn starch pastes (10% w/w) with and without xanthan gum (0.3% w/w) was analyzed. Pastes were frozen at different rates (0.3 to 270cm/h) and stored at −5, −10 and −20°C.Exudate production (syneresis) and rheological behavior were studied by means of capillary suction and rotational viscometry respectively. Ice recrystallization was analyzed by indirect microscopic observations using isothermal freeze fixation and amylopectin retrogradation by differential scanning calorimetry (DSC). Samples stored at −5°C (glass transition temperature) or higher temperatures were under the rubbery state evidenced by starch recrystallization. This state favored molecular mobility leading to deteriorative changes (like spongy structure formation related to amylose retrogradation). At lower storage temperatures (−10 and −20°C) under the glassy state, starch retrogradation was not detected and deteriorative changes can be related to ice recrystallization.The addition of xanthan gum minimized amylose retrogradation, syneresis and rheological changes, however, its presence did not prevent ice recrystallization nor amylopectin retrogradation.
Holes in Starch Granules: Confocal, SEM and Light Microscopy Studies of Starch Granule Structure
Authors: Baldwin Paul M. , Adler Jeremy , Davies Martyn C. , Melia Colin D. 
Published: November 2006

AbstractFollowing an initial observation of putative holes within potato starch granules during observation in a medium with the same refractive index, the internal architecture of starch granules has been investigated using confocal, scanning electron and light microscopy. These complimentary microscopy techniques confirmed the existence of holes at the hilum of potato, rice and wheat starch granules. Observations were made with minimal sample preparation to avoid the generation of artifactual holes. Using image analysis we have quantitatively measured the occurrence and the size distribution of holes and linked their appearance to the drying of the granule.
Hydrothermische Behandlung von Stärke in Gegenwart von α‐Amylase Teil 2: Einfluß einer hydrothermischenzymatischen Modifizierung auf die Quellungstemperatur von Weizenstärken
Authors: Stoof Gisela , Kruse Hans‐Peter , Anger Horst 
Published: November 2006

AbstractBei der hydrothermischen Behandlung von Weizenstärke in Gegenwart von Bakterien‐α‐Amylase wird auf die Gewinnung der modifizierten Reststärke bei maximaler Verschiebung der durch DSC‐Messung bestimmten Quellungstemperatur Tmax und einer hohen Ausbeute orientiert. Die Temperung der kornförmigen Stärke in Gegenwart von Enzym ergibt bei Temperaturen unterhalb der Quellungstemperatur (50°C) dieselbe Tmax‐Verschiebung wie die Temperung in Wasser. Auf Grund des laufenden enzymatischen Abbaus von angequollenem Material können jedoch höhere Reaktionstemperaturen angewandt werden, wodurch die Temperung effektiver wird. Der gebildete Maltosesirup verlangsamt die Tmax‐Verschiebung und schützt gleichzeitig das Stärkekorn. Weizenstärke kann mit einer Ausbeute von 70% und einer Tmax‐Verschiebung von 8K innerhalb von 24h getempert werden.
Eigenschaften von Gießfilmen aus nativen und chemisch modifizierten Stärken
Authors: Funke Ulrike , Lindhauer Meinolf G. 
Published: November 2006

AbstractAus Kartoffel‐, Markerbsen‐ und Amylomaisstärke wurden Stärkeacetate und ‐hexanoate niedrigen und hohen Substitutionsgrades (DS = 0,1‐2,8) hergestellt und als Ausgangsmaterialien zur Herstellung von Gießfilmen im Labormaßstab eingesetzt. Ziel der Arbeit war es, den Einfluß der Stärkeart und der Derivatisierung auf bestimmte Filmeigenschaften, wie Zugfestigkeit und Reißdehnung sowie Wasseraufnahmen und Löslichkeiten zu untersuchen.Aus den nicht oder nur teilweise substituierten Stärken wurden nach Zugabe von Weichmachern flexible, transparente und wasserlösliche Filme erhalten, während aus den vollständig substituierten Stärken wasserunlösliche Filme hergestellt wurden.Der bekannte Amylosevorteil bei der Filmherstellung zeigte sich erst nach der Derivatisierung. Im Fall der Markerbsen‐ und Amylomaisstärke reichten bereits niedrige Substitutionsgrade aus, um die mechanischen Eigenschaften der Filme, sowohl die Zugfestigkeit als auch die Reißdehnung, deutlich zu verbessern.
The Relation between Calcium Sequestering Capacity and Oxidation Degree of Dicarboxy‐Starch and Dicarboxy‐Inulin
Authors: Besemer Arie C. , van Bekkum Herman 
Published: November 2006

AbstractThe objective of this study was to establish the relation between the calcium sequestering capacity (SC) of dicarboxy‐starch and that of dicarboxy‐inulin, and the oxidation degree of these products. An S‐type curve is obtained when plotting the SC of oxidized starch versus the degree of oxidation. By contrast the sequestering capacity of dicarboxy‐inulin increases linearly with the degree of oxidation. The difference in behaviour of these materials can be attributed to the fact that upon starch oxidation the favourable oxydiacetate structure is obtained only after substantial conversion, whereas in inulin this structure is obtained immediately and is present in each oxidized fructose unit.
Distribution of Partial Digestion Products of Hydroxypropyl Derivatives of Maize, Waxy Maize and High Amylose Maize Starches
Authors: Azemi B. M. N. Mohd. , Wootton M. 
Published: November 2006

AbstractPorcine pancreatic α‐amylase digests of native and hydroxypropyl derivatives of maize (NM), waxy maize (WM) and high amylose maize starches (HA) were subjected to ethanolic fractionation into oligosaccharide and polysaccharide fractions. Both fractions of the partial digests were analysed for blue values, reducing values, total carbohydrates, average degree of polymerisation and molar substitution (MS). Distribution of hydroxypropyl groups between the fractions varied depending on starch type and level of substitution with the polysaccharide fraction being higher in MS. Blue values (BV) and average degree of polymerisation (DP) tended to decrease with digestion while reducing values (RV) increased.
Retrogradation of Potato Starch as Studied by Fourier Transform Infrared Spectroscopy
Authors: van Soest J. J. G. , De Wit D. , Tournois H. , Vliegenthart J. F. G. 
Published: November 2006

AbstractRetrogradation kinetics for a potato starch‐water system (10% w/w gel) was monitored by Fourier Transform Infrared spectroscopy and compared with waxy maize starch. The spectra showed the C‐C and C‐O stretching region (1300‐800 cm−1) to be sensitive to the retrogradation process. A multi‐stage process was observed during the retrogradation of potato starch and characterized as the formation of short‐ and long‐range order. The first stage was characterized as the formation of helices and the fast formation of crystalline amylose regions. The second stage was described as the induction time for amylopectin helix aggregation. Stage three was described as the helix‐helix aggregation and the crystallization of amylopectin. The overall‐first order calculated rate constant of potato starch was (9.6±1.4) 10− 3h−1. The calculated rate constant were in agreement with the known difference in retrogradation kinetics of waxy maize and potato starch. The effects were explained by the differences in retrogradation rate of amylopectin and amylose. Potato starch consists of amylose as well as amylopectin. Whereas amylose crystallization occurs within a few hours, amylopectin crystallization is slow and takes a few weeks.
Microwaves in Physical and Chemical Modifications of Starch
Authors: Muzimbaranda C. , Tomasik P. 
Published: November 2006

AbstractMaize, cassava and potato starch was modified by the low and medium low energy of microwave radiation. Plain starch undergoes dextrinization. Starch blended with TiCl4 gave gels of low viscosity. Reactions with formaldehyde as well as with acetylene gave products of enhanced viscosity.
Purification and Properties of the Raw Starch Digesting Amylase from Penicillium brunneum No. 24
Authors: Haska Nadirman , Ohta Yoshiyuki 
Published: November 2006

AbstractRaw sago starch digesting amylase was obtained from Penicillium brunneum No. 24. The crude enzyme from this strain contains carboxymethylcellulase (CMC‐ase), avicelase, α‐amylase and α‐glucosidase. Affinity chromatography (α‐cyclodextrin‐Sepharose 6B) of the enzyme after ammonium sulfate fractionation, Toyopearl HW‐55F gel filtration, DEAE‐Sephadex A‐50 and DEAE‐cellulose chromatographies fractionation steps, resulted in a homogeneous glucoamylase. SDS‐polyacrylamide gel electrophoresis of purified enzyme showed a single band, and a molecular weight of 80,000 for the native glucoamylase from Penicillium brunneum No. 24 was observed. After modification of the native glucoamylase with subtilisin, the molecular weight was reduced to 76,000. It lost the ability to digest and adsorb onto raw starches. However, its ability to digest gelatinized starches was preserved.