bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probleme der gelchromatographischen Molekulargewichtsbestimmung von Stärkemolekülen
Authors: Klingler R. W. 
Published: November 2006

AbstractDie Gelpermeationschromatographie (GPC) an porösem Glas (CPG) unter Einsatz eines Differentialrefraktometers ist ein schnelles und vorteilhaftes Verfahren zur Fraktionierung und Charakterisierung von Biopolymeren. Im Rahmen dieser Arbeit wird über die Erfahrungen und die Probleme mit dieser Analysentechnik bei der Untersuchung der Molekülgrößenverteilung von nativen und modifizierten Stärken berichtet und der Einfluß der experimentellen Bedingungen auf das Elutionsverhalten dargestellt. Es wird gezeigt, daß die Anwendbarkeit des Verfahrens und die Aussagekraft der Ergebnisse vom Stärketyp, von der Löslichkeit der Stärke, von der Trenncharakteristik sowie von der Eichung der Säule abhängen.
An ESR Spin Probe Study of Potato Starch Gelatinization
Authors: Windle J. J. 
Published: November 2006

AbstractPotato starch granules in excess water exhibit three distinct starch‐water stages between approximately 25° to 50°C, 50° to 70°C, and 70° to 90°C corresponding to a pre‐gelatinization, a gelatinization and a post‐gelatinization stage, respectively. The mobility of the absorbed water and the starch‐water interaction in the first two stages depends strongly upon the initial state of hydration of the granules. By the end of the gelatinization stage, the mobility of the water in the gel is the same regardless of the initial state of hydration of the granules. Upon cooling to room temperature the mobility of the gel water decreases to a corresponding viscosity of about an order of magnitude greater than for liquid water.
Production Methods of D‐Mannitol
Authors: Makkee M. , Kieboom A. P. G. , van Bekkum H. 
Published: November 2006

AbstractThe present commercial production of D‐mannitol, a valuable nutritive sweetener, takes place by hydrogenation of 1:1 D‐glucose/D‐fructose mixtures over nickel. The low D‐mannitol yield (25 — 30%), however, asks for the development of alternative procedures. A literature survey of the various production methods is given, including some other possible combinations of known procedures. It is concluded that the simultaneous use of glucose isomerase and copper‐on‐silica (combi‐process) is a promising procedure for the preparation of D‐mannitol from D‐glucose or D‐glucose/D‐fructose syrups.
Enhanced Digital Control of a Mechanical Recompression Evaporator in a Modern Fructose Refinery
Authors: Dietrich D. 
Published: November 2006

AbstractFixed‐speed, motor‐driven recompression evaporators are inherently more difficult to bring up from a cold start than variable speed turbine‐driven ones. They also need more careful operator attention during throughout changes. These difficulties are mostly caused by the choking action of the motor driven compressor's main control device the variable turbine‐inlet guide vanes. Compression of fugitive water vapors so far suffers from another problem not encountered during turbo‐compression of gas or air: no reliable simple flow element for compressor discharge is in general use. Thus standard compressor surge control schemes involving measured flow will not work. The method presented involves a two‐tier hierarchial control scheme. The usual flow, pressure, temperature and density loops are directly controlled by electronic analogues of P‐I‐D‐controllers, some even having conventional cascade linkages. Those P‐I‐D‐controllers, in turn, have their setpoints coordinated by a supervisory master computer as though they were all cascaded. The results of the control scheme are intended to the following:
Increased safety during start‐up because not only guide ‐vane opening but also heat‐up and purge‐out are monitored via a consistent algorithm, not left to an operator's whim.
Reliable and safe turn‐down capability of the evaporator over a range of from full to about 1/3 design capacity.
Reduced need for operator attention since the control scheme will handle most plant upsets by itself.
It was mostly the latter of the hoped‐for advantages which prompted development of the method, since the user wanted to keep down the number of highly trained process operators needed to man the centrally‐located control room of the syrup refinery.
Studies on the Functional Characteristics and Digestibility of Starches from Phaseolus vulgaris Biotypes
Authors: Hoover R. , Sosulski F. 
Published: November 2006

AbstractThe functional properties of starches from black bean, kidney bean, navy bean, northern bean and pinto bean, all biotypes of Phaseolus vulgaris, were examined. Starch granule sizes ranged from 22 – 39 μm (length) to 19 – 28 μm (width) and shapes varied from elliptical to oval. Amylose content ranged from 30.2 – 37.3%. A highly ordered crystalline structure of granules (Ca) was suggested by restricted swelling power and solubility, resistance to α‐amylase attack, high gelatinization temperature and stable amylographic viscosities. Moreover, the existence of a crystalline structure of the highest and lowest order of stability among the Phaseolus starches was indicated for pinto bean and black bean, respectively, which were substantially different than those of kidney, northern and navy bean. The higher stability of pinto bean starch indicated a higher degree of associative bonding forces, namely, hydrogen and covalent, between oxygen and hydrogen atoms of closely packed parallel amylose chains. The wide range in amylographic viscosities was a reflection of crystalline stability, amylose exudation, granule swelling and pH of slurry. Gels exhibited a higher degree of retrogradation at +4 °C than at – 15 °C. Scanning electron microscopy showed that α‐amylase‐treated corn starch granules were degraded from the inside out by the formation of large circular holes, whereas those of kidney bean were less extensively degraded and showed only scaling and roughening of the surface as evidence of granule deterioration.
Preparation and Calcium Complexation Properties of a Series of Oxidized Polysaccharides. Structural and Conformational Effects
Authors: Nieuwenhuizen M. S. , Kieboom A. P. G. , van Bekkum H. 
Published: November 2006

AbstractA number of polysaccharides of the starch type, including maltodextrins and cyclodextrins and some other well‐known polysaccharides have been oxidized by periodate/chlorite (two‐step method) or hypochlorite (one‐step method), yielding ring‐opened polycarboxylates. The oxidation products from the starch type show by far the best calcium complexing properties and have potential application as phosphate substitutes in detergent formulations.A relatively sharp increase in calcium complexing ability is observed at a degree of polymerization of about ten, whereas just a slight further improvement occurs at higher degrees of polymerization. This phenomenon is explained by the formation of helix structures which contain efficient Ca(II) complexing sites. This idea is supported by 17O NMR measurements showing that oxidized starch type compounds with m > 10 behave as heptadentate ligands.
Structural Characteristics of Gelatinized Starch
Authors: Varriano‐Marston E. , Zeleznak K. , Nowotna A. 
Published: November 2006

AbstractDescriptions and interpretations of gelatinized starch structure are dependent on electron microscopical sample preparation techniques. Complete destruction of starch granule integrity is effected by slow freezing and fast drying procedures. Fast freezing rates and controlled sublimation of ice are necessary for maximum structural preservation. Solvent dehydration methods produce a film on gelatinized starch granule surfaces so that their porous nature is not revealed. In addition, agglomeration and compaction of the fine fibrous network of starch exudate is effected by solvent dehydration techniques.
Bestimmung der funktionellen Gruppe und des durchschnittlichen Substitutionsgrades von Carboxymethylstärke
Authors: Kessel H. 
Published: November 2006

AbstractFür die Charakterisierung chemisch modifizierter Stärkederivate ist die Kenntnis ihres Anteiles an funktionellen Gruppen erforderlich. Bei der Carboxymethylstärke ist es die CH2COONa‐Gruppe, deren molare Relation zu den Glucose‐Einheiten des Stärkemoleküls den durchschnittlichen Substitutionsgrad ergibt.Mit der vorliegenden, für die Fabrikationskontrolle ausgearbeiteten Analysenmethode wird die CH2COONa‐Gruppe der Carboxymethylstärke durch Fällung ihres Kupfersalzes und Rücktitration des überschüssigen Kupfers im Filtrat mit Ethylendiamintetraacetat gegen Murexid‐Indikator bestimmt.
Cyanoethylated Starch Thickeners as Substitutes for Sodium Alginate in Printing with Reactive Dyes
Authors: Hebeish A. , Abdel‐Thalouth I. , Ibrahim M. A. , Elzairy M. R. 
Published: November 2006

AbstractCyanoethylated starches were prepared by reacting rice starch with acrylonitrile in presence of sodium hydroxide. The suitability of the modified starches in printing cotton fabrics with reactive dyes was investigated through application of pastes containing cyanoethylated starches and reactive dyes to cotton fabric, fixation of the prints by steaming or thermal treatment, assessment of colour strength and overall fastness properties of the prints, examination of rheological properties and carrying out parallel experiments using sodium alginate, unmodified starch and alkali‐treated starch. Cyanoethylated starches particularly that containing 1.75% N proved to be a potential thickener for printing cotton with reactive dyes.
A Comparative Study of the Effect of Acetylation on Starches of Phaseolus vulgaris Biotypes
Authors: Hoover R. , Sosulski F. 
Published: November 2006

AbstractEnzyme hydrolysis, X‐ray diffraction, differential scanning calorimetry and Visco/Amylo/Graphy were used to examine the strength of associative bonding forces between starch chains of native legumes. Addition of acetic anhydride resulted in unequal degrees of substitution. Scanning electron microscopy revealed no differences between the external morphology of native and acetylated starches. Similarities in the X‐ray diffraction patterns of native and acetylated starches indicated that acetyl groups mainly entered the amorphous regions. On acetylation, decreases in starch hydrolysis, gelatinization temperatures, enthalpies of gelatinization, extent of viscosity increase during the holding period at 95°C and syneresis, and increases in 95°C viscosity, set‐back and amylose exudation were observed. It appeared the extent of distribution of the acetyl groups between the amylose and the amorphous regions of the amylopectin fraction varied among legume biotypes, and differences existed between legume starches with regard to the ratio of the concentration of the acetyl group at the 2—O position relative to that at 6—O.
Characterization of Pinhão Starch. Part II. Rheological Properties of the Pastes
Authors: Cereda M. P. , Wosiacki G. 
Published: November 2006

AbstractPinhão starch paste shows a viscoamylographic pattern that is not usual for cereal or tuber sources, being more closely related to leguminosae starches. The gel is highly resistant to heat and mechanical stirring and it shows a relatively low retrogradation. There is no peak viscosity and the gel is not easily cooked. The opacity is similar to that of cassava starch paste, when hot, and to that of corn, in cold conditions. Viscoelastic characteristics of the paste show a short‐bodied behaviour, more similar to corn starch paste, although some elasticity may be clearly observed. The rheological properties of this starch make it a potential additive for blending with other starches, mainly for use in some processed acid foods submitted to cold storage.
A Comparison of the Susceptibility of Two Commercial Grades of Wheat Starch to Enzymic Hydrolysis and their Resultant Oligosaccharide Product Spectra
Authors: Atkins D. P. , Kennedy J. F. 
Published: November 2006

AbstractSolutions of two commercial fractions of wheat starch, which are separated by their granule size, have been found to differ both in their susceptibility to hydrolysis by α‐amylase and in the oligosaccaride spectra of their resultant hydrolysates. These effects have been ascribed to a reduced proportion of amylose and a higher degree of (1 → 6) branching identified in the starch of the smaller granules.
Changes in Crystallinity and Gelatinization Phenomena of Potato Starch by Acid Treatment
Authors: Komiya T. , Nara S. 
Published: November 2006

AbstractThe hydrolysis of potato starch by 1‐N H2SO4/30% ethanol aqueous solution at 45°C increased linearly with increasing of hydrolysis time for 14 d. The relative crystallinity of native starch showed 0.343 and 0.350 by symmetrical reflection and transmission techniques, resp. The increasing ratio of relative crystallinity to hydrolysis time corresponded very closely with that of 1/hydrolysis residue up to 14 d. These facts suggest that only the amorphous region of the starch granules will be hydrolyzed by the acid. By differential scanning calorimetry the calorimetric enthalpy of potato starch containing about 200% moisture content was found to stay largely unchanged by acid treatment for 6 d. The swelling power at 70° and 80°C of potato starch reached to the minimum value and, moreover, from the gel‐chromatogram patterns of the acid‐treated starches, the crystalline region of the starch granules may begin to deteriorate slightly by acid treatment for more than 6 d, although the relative crystallinity by the X‐ray diffraction method increased slightly with passing of hydrolysis time.
Analytical Remarks to Explain Some Discrepancies in the Determination of Dry Matter and Starch from Potato Tubers Density
Authors: Samotus B. , Leja M. , Scigalski A. , Dulinski J. , Siwanowicz R. 
Published: November 2006

Abstract1) Air adsorbed on potato tuber surface can result the accidental error, decreasing the true value of tuber density. Some deviations from normal temperature do not seem to change substantialy the tuber density.2) The dry matter determination should be precisely reexamined in a special series of experiments. The improper method can introduce a systematic error, increasing or decreasing the results.3) It is necessary to compare mostly used methods of starch determination in potato tubers and to estimate the possible systematic errors.4) The various slope of the regression line: dry mater/starch vs. potato density, can be resulted by different factors as follows: the variable intercellular spaces, the proportional systematic errors in analytical determination, the variable dry matter density, and increasing (or decreasing) value of non‐starch substances.5) The intercellular spaces can result either a constant or a proportional systematic errors in the tuber density determination. They can be eliminated by vacuum infiltration procedure, which should be, however, verified.6) The dry matter determination seems to be difficult analytical problem and it has not been definitely solved until now.7) The Maercker's constant has been until now an open question and its variability should be verified from analytical point of view.
Extrusion Cooking in Enzymatic Liquefaction of Wheat Starch
Authors: Reinikainen P. , Suortti T. , Olkku J. , Mälkki Y. , Linko P. 
Published: November 2006

AbstractWheat starch was treated for gelatinization, partial liquefaction, and subsequent further hydrolysis by extrusion cooking together with a thermostable Bacillus licheniformis α‐amylase followed by batch incubation of the extrudates at 80°C. The degree of hydrolysis depended on the extrusion feed moisture content, enzyme concentration, mass temperature during extrusion cooking, and the length of the counter screw elements. The degree of hydrolysis was followed both by dextrose equivalent and by molecular weight distribution pattern as determined by high performance gel permeation chromatography. A reaction velocity model was shown to fit well to the kinetic data obtained. The enzyme was only incompletely inactivated by mercuric chloride suggesting the presence of also other than sulfhydryl dependent amylase.
Isosorbide. Preparation, Properties and Chemistry
Authors: Flèche G. , Huchette M. 
Published: November 2006

AbstractIsosorbide is obtained by dehydration of sorbitol and therefore can be considered as a valuable product from biomass. The acid‐catalyzed reaction gives rise to different anhydro‐compounds, but also to polymer‐like products. Kinetics of sorbitol decrease, followed with the help of HPLC, shows, remarkedly, the different reactions taking place during the dehydration. Physiocochemical properties of isosorbide are also discussed: melting temperature, specific gravity, solubility. Emphasis is put on stereochemistry aspect, pointing out the endo‐exo position of hydroxyl groups versus those of other isomers: exo‐exo for isoiodide and endo‐endo for isomannide. Some other properties such as: hygroscopicity ant thermal stability are also discussed. The chemical reactivity of the molecule is then described and some reactions analyzed, proving the interest of the cyclic conformation. Finally, a review of known applications is presented.
Thiosemicarbazones of Starch Dialdehyde and Their Biological Activity
Authors: Barabasz W. , Chociej J. , Kenit A. , Tomasik P. 
Published: November 2006

AbstractStarch dialdehyde thiosemicarbazones of various degree of substitution were prepared and their biological activity studied against some saprophytes, fungi and Mycobacterium tuberculosis.
A New Regenerable Immobilized Glucose Isomerase
Authors: Antri R. L. , Auterinen A.‐L. 
Published: November 2006

AbstractA new, immobilized glucose isomerase high productivity has been developed for isomerization of glucose into high fructose syrups. Soluble glucose isomerase fromStreptomyces rubiginosusis highly purified and electrostatically adsorbed onto a granular DEAE‐cellulose comprised of fibrous DEAE‐cellulose, food grade polystyrene and titania. The same enzyme on fibrous DEAE‐cellulose has been in commercial use in the United States since 1968. Because the soluble enzyme is electrostatically adsorbed to the carrier, the immobilized enzyme can be regenerated after use and the carrier reloaded with fresh soluble enzyme. Regeneration and reimmobilization can be repeated several times thus providing a minimum cost enzyme‐carrier system. The enzyme is tightly bound to the carrier during isomerization. The immobilized isomerase is compatible with bisulfite in the substrate sufficient to stabilize the enzyme and provide a degree of protection against infection at low isomerization temperature. High purity and high specific activity of the soluble enzyme make possible high activity levels for the immobilized enzyme with potencies of up to 1500 IGIU/g. There occurs essentially no elution of color from the immobilized enzyme during start up of isomerization. Due to the combination of low compressibility of the particles and high immobilized activity, productivities greater than 9 metric tons of 42% fructose syrup solidsPerkg of immobilized enzyme are being achieved on a commercial scale.
Molecular Composition of Starches from Growing Potato Tubers
Authors: Praznik W. , Burdicek G. , Beck R. H. F. 
Published: November 2006

AbstractThe changes in the molecular distribution of potato starch during the growth of tubers is determined by GPC (Sephacryl gel systems). After n‐butanol fractionation of amylose and amylopectin an efficient statement of the molecular weight alteration of the starch components is observed. Amylopectin of young immature tubers shows a narrow highmolecular weight distribution whereas the amylopectin of mature tubers have a broader distribution with low‐ and highmolecular weight portions. Also the branched structure is different regarding starch of small and big tubers. Amylose shows a continous increase of the molecular weight. The range up to 0.2 · 106 Dalton is diminished, the molecular weight range over 1.2 · 106 Dalton is increased. The range in between rests nearly constant. These changes in the molecular composition are observed by different potato varieties, Conny and Sieglinde. Clear differences between the amyloses and amylopectins of these two varieties are noticed. The starch components of Sieglinde have always lower molecular weights as Conny starches, just so the overlapping range is much broader.
An Evaluation of Cassava Starch as a Gelling Material for Electrochemical Salt Bridges
Authors: Iwunze M. O. , Nnodimele R. A. 
Published: November 2006

AbstractCassava starch was investigated for its potential use as a gelling material for electrochemical salt bridges. Different electrolytes, KCl, NH4 and NH4NO3, were mixed with the starch and the resulting voltage of a Zn–Cu Cell in which it is used as a salt bridge was measured. The observed voltage agreed with the theoretical voltage within 3.6% error. It was observed that the starch and ammonium nitrate electrolyte produced a better blend, gave more reproducible values and has the lowest resistance of all the other electrolyte‐starch mixtures.
Tepary Bean Starch. Part I. Physico‐chemical Properties
Authors: Abbas I. R. , Berry J. W. 
Published: November 2006

AbstractStarch of high purity was isolated by a simple procedure from tepary beans (Phaseolus acutifolius var. latifolius). Granules were spherical to oval with a birefringence pattern similar to that of other legume starches. Under SEM they appeared smooth with no evidence of fissures. They showed a normal distribution of diameters with a range of 15.5–59.8 μ and a mean of 33.5 μ. Tepary starch had an amylose content of 30.7% and a gelatinization temperature range of 70.5–84.0°C. Other properties were also determined. Fractionation provided an amylose fraction with a β‐amyloysis limit of 76.3% and an average DPη of 618. The amylopectin fraction had an average magnified image values of 33, 22 and 10 glucose units respectively.
Studies on the Application of Maltogenic Amylase in the Production of Maltose Containing Syrup
Authors: Słomińska L. , Starogardzka G. 
Published: November 2006

AbstractThe thermostable and relatively acid stable maltogenic amylase produced by Bacillus stearethermophilus was investigated. (The investigations have been carried out with the aim of producing high maltose syrup from liquefied potato starch. The results of the investigations showed that the application of the maltogenic enzyme made possible to produce potato syrup containing 70–80% maltose from DE 12 enzyme liquefied starch in concentration of 30–35%.
Graft Polymerization of Acrylamide onto Starch Using Ferrous‐Starch Thiocarbonate‐Persulphate Redox System
Authors: Bayazeed A. , Farag S. , Hebeish A. 
Published: November 2006

AbstractGraft copolymerization of acrylamide (Aam) onto starch using ferrous‐starch thiocarbonate‐persulphate redox system was investigated under different conditions including alkali concentration in the precarbon disulphide treatment, potassium persulphate concentration, ferrous ion concentration, monomer concentration, pH of the polymerization medium, polymerization temperature, use of solvent/water mixture instead of aqueous medium, and liquor ratio. The role of thiocarbonation on the magnitude of grafting of acrylamide onto starch has been studied with respect to K2S2O8 and ferrous ion concentrations. The graft yield was significantly favoured in acidic medium as well as by increasing the persulphate concentration, acrylamide concentration, and polymerization temperature. Carbon tetrachloride constitutes the optimal medium for polymerization. Grafting was also favoured in either higher or lower liquor ratios.