bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production and Application of a Maltogenic Amylase by a Strain of Thermomonospora viridis TF‐35
Authors: Takahashi K. , Totsuka A. , Nakakuki T. , Nakamura N. 
Published: November 2006

AbstractAn extracellular and thermostable maltogenic amylase‐producing moderate thermophile (Thermomonospora viridis TF‐35), which grew well at 28–60°C, with optima at 45°C and pH 7, was isolated from soil. Maximal enzyme production was attained after aerobical cultivation for 32 h at 42°C with a medium (pH 7.3) composed of 2% (w/v) soluble starch, 2% gelatin hydrolyzate, 0.1% K2HPO4 and 0.02% MgSO4 · 7H2O. The partially purified enzyme, which was most active at 60°C and pH 6.0 and stabilized with Ca2+, converted about 65, 80, 75, 75, 65 and 60% of maltotriose, maltotetraose, maltopentaose, amylose, amylopectin and glycogen into maltose as a major product under the conditions used, respectively. Glucose and small amounts of maltooligosaccharides were also formed concomitantly as by‐products. The molar ratio of maltose to glucose from maltotriose were larger than 1 during all stages of the hydrolysis. About 70 and 76% of 25% (w/v) potato starch liquefites having a 3.5 DE value were converted into maltose by the enzyme in the absence and presence of pullulanase during the saccharification, respectively. About 90 and 94% of the starch liquefites were also converted into maltose with relatively low contents of maltooligosaccharides by the cooperative 2 step reaction with the enzyme after obtaining starch hydrolyzates containing about 85 and 90% maltose by the simultaneous actions of soybean ß‐amylase and debranching enzymes.
Saponification of Graft Copolymers of Sodium Salt of Partially Carboxymethylated Amylose and Its Water Absorbency
Authors: Shah S. B. , Patel B. K. , Patel C. P. , Trivedi H. C. 
Published: November 2006

AbstractThe grafting of acrylonitrile (AN) onto amylose and sodium salt of partially carboxymethylated amylose samples having different degrees of substitution has been carried out using ceric ammonium nitrate (CAN) as redox initiator. The saponification of all the PAN‐containing graft copolymers has been carried out by methanol precipitate method. The water retention values of all the graft copolymers have been measured and compared. The results have been discussed.
Studies on Alkali‐Modified Cassava Starch ‐ Changes of Structural and Enzyme (α‐Amylase) Susceptibility Properties
Authors: Raja K. C. M. 
Published: November 2006

AbstractProperties of cassava starch could be modified by subjecting to alkalitreatment under controlled experimental conditions. Modified starch samples showed lower amylose content and higher alkali number. Compared to untreated starch samples, alkali modified starches had higher α‐amylase (Bacillus sp.) susceptibility. The properties could be advantageously made use of for preparing maltodextrins having DE 20–23.
Microscopic Evaluation of Hydroxypropyl Potato Starch Granules During Treatment with Urea
Authors: Kim Hak‐Ryang , Hermansson A.‐M. , Eriksson E. 
Published: November 2006

AbstractA microscopic methodology was devised for the quantitative measurement of the changes in light intensitiy during the loss of birefringence of starch granules in aqueous urea under polarized light. This has been adapted to a native potato starch, hydroxypropyl potato starches of varying molar substitution (M.S.) and a hydroxypropyl and cross‐linked potato starch. Several of the factors influencing the measurement results such as urea concentrations, sodium sulphate content and temperature were examined. The hydroxypropyl potato starches rapidly lost their birefringence with increasing M. S., and the relationship between the M. S. and the rate of changes in light intensity was found. There were marked differences in the morphology of the swollen shapes of granules between hydroxypropyl potato starch, and hydroxypropyl cross‐linked potato‐starch.
Feinstruktur und Hyperfeinstruktur von klinisch verwendeter Hydroxyethylstärke
Authors: Sommermeyer Klaus , Hildebrand Ulrich , Cech Franz , Pfitzer Edith , Henning Klaus , Weidler Burghard 
Published: November 2006

AbstractAn einer Reihe unterschiedlicher Proben Hydroxyethylstärke wurden durch Multidetektions‐HPGPC die Mark‐Houwink‐Parameter, sowie über die gaschromatographische Methylierungsanalyse neben der Verzweigung die molekularregionsspezifischen Substitutionsgrade MS und DS und die Substitutionsmuster gemessen. Innerhalb der Molekularregionen nichtreduzierender Kettenenden, Verzweigungseinheiten sowie linearer Kettenglieder ergeben sich charakteristische Unterschiede in bezug auf die Substitution, die diskutiert werden. Hydroxyethylstärken, welche aus enzymatisch durch Amylase vorbehandelter Wachsmaisstärke hergestellt wurden, weisen einen signifikant höheren Anteil an Verzweigung auf, verglichen mit säurehydrolytisch vorbehandelter Stärke. Die klinische Relevanz der Ergebnisse wird diskutiert.
Purification and Characterization of a β‐Amylase of Hendersonula toruloidea
Authors: Odibo F. J. C. , Okafor N. , Tom M. U. , Oyeka C. A. 
Published: November 2006

Abstractβ‐Amylase produced by Hendersonula toruloidea was purified to homogeneity by salting out with ammonium sulphate, ion‐exchange chromatography on DEAE‐cellulose and gel‐filtration on Sephadex G‐75. The relative molecular mass of the enzyme was estimated to be 60,000 by gel filtration. The enzyme was optimally active at pH 6.0 and 60°C, stable between pH 6 and 8 (24 h) and retained 74% activity at 70°C (30 min). It was strongly activated by Na+ but inhibited by Hg2+, Zn2+ and Cu2+. The enzyme hydrolyzed amylopectin (Km 0.42 mg/ml) forming maltose, maltotetraose and unidentified maltooligosaccharide, and hydrolyzed soluble starch (Km 0.3 mg/ml) and glycogen (Km 0.5 mg/ml) forming maltose and unidentified maltooligosaccharide.
Characterization of High‐amylose Type Endosperm Starches of Rice Plants Cultivated in Asia
Authors: Fuwa H. , Okuno K. , Asashiba R. , Kikuzaki H. , Asaoka M. , Inouchi N. , Sugimoto Y. 
Published: November 2006

AbstractStarch granules were prepared from 14 indica rice grains which were collected from various places of Asia and had the amylose content of 28% and over by a blue value method. The starches were high‐ and medium‐amylose types by the enzymatic and chromatographic method. However, none of them belonged to the type of high amylose mutants which were induced by the chemical mutagen treatment of a japonica rice cultivar: Kinmaze and possessed similar characteristics of endosperm starch to that of the amylose‐extender (ae) mutant of maize (Zea mays L.).
Chromatographische Untersuchungen zur Polydispersität von Hydroxyethylstärke
Authors: Sommermeyer Klaus , Cech Franz , Hildebrand Ulrich , Pfitzer Edith , Baumbach Cornelia 
Published: November 2006

AbstractEine repräsentative Probe von einer klinisch verwendeten Hydroxyethylstärke wurde mittels semipräparativer HPGPC in enge Molekulargewichtsfraktionen im Bereich von ca. 3 000 bis 800 000 D aufgetrennt. Ausgangsprobe und ausgewählte Einzelfraktionen wurden durch gaschromatographische Methylierungsanalyse in bezug auf die Substitutionsgrade MS und DS charakterisiert, wobei diese nach Substitutionsposition C2, C3 und C6 der Anhydroglucosen und deren glycosidische Bindungsart α‐1, α‐1,4 bzw. α‐1,4,6 unterschieden wer‐den. Ebenfalls ermittelt wurde die Polydispersität in bezug auf die Verzweigung.Weiterhin werden die durch Multidetektions‐HPSEC ermittelten Kenngrößen zur Molekulargewichtsverteilung und die Mark‐Houwink‐Parameter angegeben. Die Daten zeigen insgesamt eine weitgehende Homogenität der Ausgangsprobe in bezug auf die gemessenen Parameter. Ihre klinische Relevanz wird diskutiert.
Chain Length Specifity of Cyclodextrin Glycosyltransferase
Authors: Vetter Dirk , Thorn Werner 
Published: November 2006

AbstractBacillus macerans CGTase recognizes the terminal 6 glucose units of the non‐reducing end of α‐(1→4)‐glucans. Analysis of the chain‐length distributions produced by the action of CGTase on well‐defined maltodextrins gave information on the enzyme's specifity in regard of the size of the transferred glucanosyl‐moiety.It was found that in the presence of α‐cyclodextrin, maltohexaosyl‐groups could be highly specifically coupled to an acceptor like maltose. The product, maltooctaose, appeared in a yield of 45 % molar amount. The affinity for hexaosylresidues was explored by using homodisperse substrates from glucose to maltotriadecaose. HPTLC‐analysis of the product patterns in early states of CGTase catalyzed reactions revealed that the yield of the primary coupling product decreased with increasing DP. This was due to the effect, that disproportion was more rapid on higher oligomers. The intermolecular transfer of glucanosylgroups was also found to be size‐dependent, inasmuch as the relative CGTase transfer activity decreased gradually from maltohpxaosyl‐ to glucosylresidues. In an investigation of the enzymic degradation of maltodextrins maltononaose gave the highest yield of α‐CD.
Coupling of 1‐Aminododecan to Starch by Bromine Oxidation and Reductive Amination
Authors: Salomonsson B. Ann‐Christine , Theander Olof 
Published: November 2006

AbstractConjugates of potato starch have been prepared by coupling of bromine oxidized starch to 1‐aminododecan by reductive amination. The starch was oxidized at two different levels of molar ratios bromine/starch (1/20 and 1/5) and at two different temperatures (22deg;C and 94deg;C). The content to introduced keto functions was highest for the 1/5 sample oxidized at 22deg;C. The GPC (gel permeation chromatography) analyses of the molecular weight showed that oxidation 1/5 at 94deg;C provided an oxidized starch with molecular weight below 50,000 whereas the other oxidation conditions gave products with higher molecular weights. The keto functions of the oxidized starch was aminated with 1‐aminododecan by reductive amination at different temperatures (22deg;C and 80deg;C) and reaction times. The proportion of coupled amine was highest at 80deg;C after 3 h.
Modification of Starch‐Based Hydrogels Through Grafting by a New Chelating Monomer
Authors: Mikhael Michael G. , Kulicke Werner‐M. 
Published: November 2006

AbstractNative maize starch was grafted by N‐acryloyl‐N′‐cyanoaceto‐hydrazide (ACAH) using potassium persulfate as a free radical initiator in aqueous medium. Spectral (FT‐IR) and elemental analyses were used in combination to elucidate both the structure and composition of the thoroughly washed grafted samples. Gelation of the produced grafted samples has been carried out in alkaline medium using sodium trimetaphosphate (Na3P3O9) as a cross linker. The effects of temperature and sodium hydroxide, substrate and crosslinker concentrations were found to be significant in determination of the rheological properties of the prepared modified gels. The influence of grafting ratio and cross‐linker concentration on the gel swelling ability was investigated in deionized water as well as in sodium and potassium chloride 10−2 molar solutions. The produced gels showed a great tendency towards complexation with many metal cations. Chelation with Cu(II), Ni(II) and Cr(III) chloride solutions has been spectrophotometrically investigated. Stability constants of the formed complexes were found to be of the order of 107.
Preparation and Characterization of Copolymers of Modified Starches and Polyacrylonitrile
Authors: Honig David H. , Carr Merle E. 
Published: November 2006

AbstractStarch graft polyacrylonitrile (S‐g‐PAN) copolymers were prepared from a commercial unmodified cornstarch and from three chemically modified commercial cornstarch products including Amaizo 395 (highly acid modified, HAM), Amaizo 590 (highly hypochlorite oxidized, HHO) and Amaizo 791D (hydroxyethyl, highly acid modified, HEHAM). Using similar reaction conditions and ratio of monomer to starch (1:1), the percentages of PAN in the copolymers ranged from 39% for the unmodified starch to 48% for the modified starches. Only 5% of the PAN of the copolymer prepared from unmodified starch could be extracted by dimethylformamide (DMF) treatments compared to 22–28% for copolymers prepared from the modified starches. However, copolymers from the modified starches apparently contained relatively high proportions of low‐molecular‐weight copolymer along with homopolymer. Acid hydrolysis treatment of the DMF insoluble and DMF soluble fractions to remove starch from the various copolymers gave essentially quantitative yields of PAN. However, these PAN samples exhibited large differences in DMF solubility. The copolymer from the HHO starch was by far more soluble in DMF, had the lowest number average molecular weight, and had a grafting frequency of 2.5–3 times greater than those of the other copolymers. This study indicated that hypochlorite modified starch substrates may be particularly suitable for obtaining copolymers with widely different properties than copolymers having the acid modified starch substrates.
13C‐NMR Spectroscopic Detection of Malto‐oligosaccharide Complexes
Authors: Vetter Dirk , Thorn Werner 
Published: November 2006

AbstractFragments of amylose were enzymatically synthesized and purified to α‐(a→4)‐glucans of well defined degress of polymerization by preparative size exclusion chromatography. Maltooligosaccharides from DP 3 to 12 were subjected to 13C‐NMR‐spectroscopy.The addition of iodine as a complexing agent selectively affected the carbon atoms involved in the glycosidic bond. Resonances of C‐1 and C‐4 experienced a dramatic downfield shift. This is interpreted as a change of conformation of the amylose helix. The shift differences can be measured conveniently and be used for calculations of complex stability constants. Maltohexaose and higher saccharides gave strong effects upon complexation, indicating that one helical turn brings about a gain in helical stability. No lower chain‐length limit for the complex‐forming capacity was observed. Even the smallest fragments of amylose showed complexing behaviour.
Determination of the Potato Starch Content in a Slurry by an Areometer
Authors: Potze Jan 
Published: November 2006

AbstractThe determination of the quantity of starch per volume (kg/m3) in a slurry of potato starch in water by measuring the density of the slurry with a standard areometer and the temperature is reviewed. A formula is developed in which occur two physical constants of potato starch (soaked in water): the density at 20°C and the temperature correction factor. The constants are calculated from measurements in starch slurries. In this report the method is given. A limited number of recent measurements resulted in the given preliminary constants. It showed that the density of the starch (soaked in water) differs between never dried starch and dried and reslurried starch. Starch tables can be made with the help of the developed formulas.
Starch Derivatives for Flocculation of Ferric Soaps
Authors: Cherian Xavier M. , Satymoorthy Poornakala , Kumar Velayyudhan N. G. 
Published: November 2006

AbstractAlthough water soluble synthetic polymers find wide applications as flocculating agents, the potential problem associated with their use is lack of biodegradability and high cost. Development of substitutes based on natural polymers can be more attractive from biodegradability point of view and the important factor here will be matching the performance.We have studied the flocculating effects of starch derivatives (cationic and anionic) for ferric soap flocculation at different pHs and compared their efficiency with synthetic flocculants like Zeetag‐63 and Floc‐acid‐25. Charge interaction between colloidal particles and polymeric flocculating agents is one of the factors that contribute to the changes in rae and extent of flocculation. :Under certain pH conditions starch based flocculants are shown to perform better than the synthetic flocculants (Zeetag‐63) and the effects are explained on the basis of variation of surface charge (measured by collid titration) of ferric soaps precipitated at different pHs.
Swelling and Reactivity of Maize Starch Granules
Authors: Hauber Richard J. , Bemiller James N. , Fannon John E. 
Published: November 2006

AbstractIt is concluded that granule swelling is required for any chemical derivatization of common yellow dent maize starch with fatty acyl chlorides in organic solvents, even for reaction at granule surfaces. It was also concluded that progressively less of hot pyridine‐swollen granules is available for reaction with fatty acyl chlorides as the carbon chain length increases from C6 to C14, with those two lengths being the approximate outside limits for partial exclusion.
Continuous Saccharification of Corn Starch in a Membrane Reactor. Part I: Conversion, Capacity and Productivity
Authors: Sims Kevin A. , Cheryan Munir 
Published: November 2006

AbstractEffects of enzyme concentration, substrate concentration and residence time on substrate conversion, reactor capacity and productivity were evaluated. As enzyme concentration increased from 1 to 6 g/L, substrate conversion also increased. Substrate conversion was essentially unchanged at enzyme concentrations greater than 6 g/L. Reactor capacity was significantly affected by both substrate and enzyme concentration. As residence time increased, substrate conversion increased 15–22%. Productivities of the continuous reactor were 10 to 20 times greater than those obtained in a batch reactor. The continuous membrane reactor was capable of producing a highly pure glucose syrup at low residence times. Due to the high levels of substrate conversion, minimal operational problems were experienced.
Comparison of Thermal and Viscoelastic Properties of Four Waxy Starches and the Effect of Added Surfactant
Authors: Gudmundsson M. , Eliasson A.‐C. 
Published: November 2006

AbstractThe waxy starches used in this investigation (maize (WM), barley (WB) and two rice starches RD4 and IR29) showed different gelatinization temperatures (GT) and enthalpies (ΔHG) measured with differential scanning calorimetry (DSC). The differences in GT and ΔHG could only partially be related to X‐ray crystallinity. The high GT waxy starches WM and RD4 retrograded to a greater extent measured with DSC and the order of increased retrogradation agreed well with the order of X‐ray crystallinity of the retrograded waxy starches. The melting temperature (TC) of the retrograded waxy starches in contrast to GT was very similar for all starches. This indicates that the temperature of the glass transition (Tg) of the amorphous regions in the starch granules controlled the onset GT and perhaps also the extent of retrogradation.Addition of cetyl trimethyl ammonium bromide (CTAB) decreased the extent of retrogradation more than 45% compared to the melting enthalpy (ΔHC) of the waxy starches without CTAB addition. The rice starch RD4 was most affected by the CTAB addition, and the WM starch the least. The viscoelastic behaviour in the temperature interval 25–90°C of 12%(w/w) gels differed between the waxy starches. The WB starch gels showed the highest storage modulus (G′) value and the lowest phase angle (δ), i. e. strongest and least viscous gels. The WM starch gels showed the lowest G′ value and the highest δ. The rice starches were in between with the RC4 starch (high GT) showing higher G′ value and lower δ than the IR29 (low GT). The viscoelastic parameters changed only slightly with increased temperature.The addition of CTAB to the waxy starch gels changed the viscoelastic behaviour of the stronger and less viscous starch gels of the WB and RD4 as their G′ value decreased and δ increased with increased temperature. The effect on WM and IR29 was only small.
Changes of Carbohydrates and Molecular Structure of Dextrins During Enzymatic Liquefaction of Starch
Authors: Nebesny Ewa 
Published: November 2006

AbstractInvestigations of potato starch hydrolysis during bacterial α‐amylase “Amylogal CS” liquefaction to a different dextrose equivalent were carried out at 85deg;C and pH 6,5. DE‐values, carbohydrate compositions and molecular structure of dextrins were investigated in starch hydrolyzate samples taken at DE‐values from 3.4 to 20.6. In the progress of liquefaction, that is at increasing DE‐values, changes in carbohydrate compositions, and there the decrease only of maltoheptaose and dextrins content in hydrolyzate were observed. Simultaneously, it was found that molecular weight and number of dextrin branchings decreased particularly rapidly to a significant degree of nearly 3.4 DE. At further increase of DE‐value during starch liquefaction the decrease of dextrins molecular weight and the number of branchings was lower and not that significant.
Developmental Changes in Properties of Sweet Potato Starches
Authors: Noda T. , Takahata Y. , Nagata T. 
Published: November 2006

AbstractSweet potato starches extracted from two varieties at different stages of development were investigated for various physicochemical properties. Average granule size increased in the early stage of development. The amylose content calculated from the blue value (BV) remained almost constant. The onset temperature (To) determined by differential scanning calorimetry (DSC) was lowest in the latest stage of development. The heat of gelatinization (ΔH) was lowest in the earliest stage of development. Digestibility by two glucoamylases tendet to be lower in the later stage of development.
Effect of Acid Hydrolysis and Ball Milling on Porous Corn Starch
Authors: Niemann Claudia , Whistler Roy L. 
Published: November 2006

AbstractPorous corn starch from glucoamylase hydrolysis of native corn starch was examined before and after cross‐linking, acid hydrolysis and dry ball milling. Cross‐linking does not significantly change the crystallinity, water absorption or gelatinisation properties but acid hydrolysis at 60°C increases, proportionately, crystallinity and water absorption capacity and decreases moisture adsorption at humidities less than 80%, in comparison to untreated porous corn starch. Highly crystalline porous starch has a fragile granule structure. Ball milling destroys crystallinity in both normal, porous, and cross‐linked or partially hydrolyzed starches. Particle sizes of 1–2m are obtained by milling dry starches for 48 h. Water absorption for milled starches is more than 200% (weight water/weight starch d.b.). Viscosities of these products were significantly reduced at high temperatures. Products formed stable gels in 25–30% dispersions in cold water.
Systematische GC/MS‐Analyse von 1,2‐O‐Ethylenglucose‐Derivaten in Hydrolysaten von Hydroxyethylstärke
Authors: Hildebrand Ulrich , Cech Franz , Rupp Daniela , Sommermeyer Klaus 
Published: November 2006

AbstractIn den Hydrolysaten von Hydroxyethylstärke konnten nach Persilylierung 16 verschiedene 1,2‐O‐Ethylen‐D‐Glucose‐Derivate mittels GC/MS nachgewiesen und identifiziert werden. Neben den üblichen Fragmenten silylierter Verbindungen bilden diese Derivate vier sehr signifikante lonen (m/z 86, 127, 229 und 227), die zur Erkennung der bicyclischen intramolekularen Glucosidierungsprodukte neben monocyclischen Hydroxyethylglucose‐Derivaten und zur Isomeren‐ und Anomeren‐Unterscheidung gut geeignet sind. Das typische Fragmentierungsverhalten persilylierter 1,2‐O‐Etn‐Glc‐Derivate wird beschrieben und die Ergebnisse durch den Vergleich mit den analogen Acetylderivaten verifiziert.
Chemical Modification of Guaran Gum Part I: Carboxymethylation in Aqueous Medium
Authors: Kamel M. , Abd El‐Thalouth I. , Amer M. Abou , Ragheb A. , Nassar S. H. 
Published: November 2006

AbstractGuar gum was isolated from the seeds and subjected to modification via carboxymethylation in aqueous medium. The modification increases its solubility in cold water, and increases the stability of its pastes to microorganisms. Regardless of the DS of these products, their aqueous solutions are characterized by non‐Newtonian pseudoplastic behaviour, and their apparent viscosity at a constant rate of shear depends on the DS as well as the measuring temperature.