bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic Hydrolysis of Starch from Jacatupé (Pachyrhizus erosus L. Urban) by Thermostable Amylolytic Enzymes
Authors: Mélo E. de A. , Vieira R. , Krieger N. , Guerra N. B. , Silva M. P. C. , Kennedy J. F. 
Published: November 2006

AbstractAn alternative source of starch obtained from jacatupé (Pachyrhizus erosus L. Urban) a tropical tuber has been characterized enzymatically using amylolytic enzymes. The best hydrolysis conditions were obtained using α‐amylase of 13.56U/ml at pH 7.0 and 80°C; amyloglucosidase of 177.5U/ml at a pH range from 3.5 to 4.0 and 70°C, respectively. Michaelis constants were determined in terms of substrate concentration; Km and Vmax for α‐amylase and amyloglucosidase were found to be 16.8g/1, 1.49g/1, 11.2μmol/h and 3.10μmol/h, respectively. Scanning electron microscopy studies suggest that the enzymes tunnelled into the granular interior of the starch granules and then hydrolysed from within, along concentric holes ‐ a well established phenomenon in the starch granules from classical crops.
Technology Assessment on Renewable Raw Materials: Potentials and Risks of the Use of Starches
Authors: Leible Ludwig 
Published: November 2006

AbstractStarch as a renewable raw material for chemical/industrial uses has a long tradition. In terms of quantity, starch ranks third behind wood and vegetable oils. In the medium term, this position will be maintained, if not improved. The volume of renewable raw materials used for fuel is even greater and expected to increase in the medium term. By means of a technology assessment on chemical/industrial and energy uses of renewable raw materials, it shall be demonstrated where the specific potentials and risks of starch use can be found. Among others, the following aspects are considered: energy and CO2 balance sheets, biodegradability and competiveness. Under the headings of „saving of raw materials (degree of self‐sufficiency)”︁, „area required (reduction of surpluses)”︁, „employment effects”︁, „contribution to CO2 reduction”︁ and „need for subsidies”︁, medium‐term (up to 2005) potential use of starch in Germany is studied relative to use of renewable raw materials in total.
Chemische und verfahrenstechnische Gesichtspunkte zur Herstellung von kationischer Kartoffelstärke durch Kochextrusion
Authors: Esan Michael , Brümmer Thomas M. , Meuser Friedrich 
Published: November 2006

AbstractEs wurden Extrusionsversuche zur Herstellung von kationischer Kartoffelstärke unter Verwendung von Kartoffelstärke, Natronlauge und 3‐Chlor‐2‐hydroxypropyltrimethylammoniumchlorid (Chlorhydrin) mit dem Ziel durchgeführt, den Einfluß der Extrusionsparameter auf die Reaktionseffizienz (R.E.) und der von ihr abhängigen Substitutionsgrad (D.S.) untersuchen zu können. Die Extrudate wurden dazu benutzt, um eine geeignete Analysenmethode zur genauen Bestimmung des D.S. zu entwickeln.Damit die notwendige analytische Genauigkeit erreicht werden kann, müssen alle stickstoffhaltigen Substanzen, die nicht chemisch an die Moleküle der Stärke gebunden sind. vor der Bestimmung des Stickstoffgehalts der kationischen Stärke quantitativ aus dieser extrahiert werden. Es konnte mit Extraktionsexperimenten gezeigt werden, daß die Extrahierbarkeit solcher Substanzen aus gemahlenen kationischen Kartoffelstärkeextrudaten von der Penetration des Lösungsmittels durch die Extrudatpartikel und der Diffusion der löslichen Substanzen in den Partikeln in das Lösungsmittel abhängt. Optimale Ergebnisse wurden für die R.E. durch Suspendieren von einem Teil gemahlenem kationischem Kartoffelstärkeextrudat in zehn Teilen Lösungsmittel erzielt, das aus 80% Ethanol und 20% Wasser (w/w) bestand. Die Suspension mußte 40min bei 80°C in einem verschlossenen Glasgefäß belassen werden. In dem für die Extrusion gewählten experimentellen Bereich konnten konstante Reaktionsbedingungen für die Kationisierung eingehalten werden. Neben der Variation der Formulierung der reaktiven Komponenten wurde ihr D. S. von der Variation der Extrusionsparameter beeinflußt. In dem für den D.S. untersuchten Bereich von 0,03 bis 0,10 wurde eine R.E. von 80% erzielt.
Re‐Examination of the Bread Firming Curve
Authors: Ovadia D. Z. , Walker C. E. 
Published: November 2006

AbstractBread firming curves are generally accepted to be continuous, positively sloped, and convex at all points. However, a review of published literature suggests this may not always be so. To investigate possible deviations from the assumed curve, a dynamic rheometry method was developed and used to measure firmness every 12h for at least 10 days. It was non‐destructive so eliminating sample variance. An interpretation of the results is as follows. The firming of each of four adjacent slices from a 1‐pound loaf showed random fluctuations, independent of adjacent slices and forming a discontinuous curve. They were analogous to quantum peaps of an electron between orbitals. Accordingly, averaging firming of the four slices was inappropriate, because fluctuations in firmness were discreet and not necessarily due to random error. Additionally, softening to a lower level and subsequent refirming to the previous higher level indidcated structural collapse and recovery. Less frequently, these quasi‐quantum leaps were upward, followed by collapse to the more prevalent trend. This binary random fluctuation, or BINARF, was interpreted as showing two possible independent firming mechanisms. These might be (1) hydrogen bonding and/or hydrophobic bonding between starch and gluten and (2) starch retrogradation.
A New Approach to the Kinetics of Colour Formation in Concentrated Carbohydrate Solutions
Authors: Imming Rainer , Stendal  , Buczys Rahel , Lehnberger Andreas , Bliesener Klaus‐Michael 
Published: November 2006

AbstractThe deduction of a kinetic model of colour formation, especially by the Maillard reaction, in heated concentrated carbohydrate solutions is described on the basis of systematic experimental studies. The main parameters of the colour formation are included such as reaction time, temperature, pH, amounts of sucrose, glucose, fructose, amino‐nitrogen and dry matter. The model is based on a three step first order consecutive reaction beginning with sucrose via glucose/fructose and dicarbonyl compounds to the colourants. The suitability of the model was tested on model experiments as well as on experiments with technical solutions in an evaporation station. It resulted in a good correspondence between measured and calculated colour values. The potentials of the model are discussed and the range of applications is pointed out.
Properties of Potato Starch in Relation to Varieties and Environmental Factors
Authors: Haase Norbert U. , Plate Jutta 
Published: November 2006

AbstractAn extensive assortment of potato varieties in connection with different growing conditions was analyzed concerning several starch quality criteria. Significant variations were evident for starch content, phosphorus content of starch, and granule size distribution. On the contrary, amylose content varied only little. Environment had influence on starch content and viscosity behaviour. Fertilization effects could not be observed. This underlines the significant variety effect. The results clearly point out that an improved accentuation of potato starch quality is possible. In connection with a selected variety spectrum and altered separation strategies new markets for potato starch utilizers can be opened within short time.
The Ultrastructure of Starch from Ultrathin Sectioning in Melamine Resin
Authors: Helbert William , Chanzy Henri 
Published: November 2006

AbstractA method is described whereby unstained native or litnerized starch granules were embedded in Nanoplast resin before being ultrathin sectioned and observed by transmission electron microscopy. As these sections were initially devoid of contrast, a mild HCl hydrolysis was applied in order to reveal the location of the granules. During this treatment, the embedding resin was etched preferentially while the granules were left almost intact. This method allowed an easy recording of electron diffraction diagrams of starch when the microscopy was done under frozen hydrated conditions. Low dose images with good contrast could also be obtained from unstained and unshadowed specimens.
Starch and Amylopectin ‐ Effects of Solutes on Clarity of Pastes
Authors: Bello‐Pérez L. A. , Paredes‐López O. 
Published: November 2006

AbstractThe effect of sucrose, glucose and sodium chloride at different concentrations on clarity of starch and amylopectin pastes was studied. It was found that clarity of amaranth, waxy corn and normal corn starch pastes tended to increase by increasing carbohydrate concentrations. The percentage of transmittance (%T) values for the same starch sample with sucrose and glucose did not present significantly differences (α=0.05). The starches with sodium chloride did not show a defined pattern. The %T for amaranth and waxy corn amylopectin pastes with all solutes tended to increase by increasing solute concentration. Interestingly, the %T values among all amylopectins at a given solute concentration were significantly different (α=0.05) probably due to different chain length proportion in such amylopectins. The same amylopectin in presence of sucrose and glucose did not show %T significantly different (α=0.05) but with sodium chloride those values were different (α=0.05).
Changes in Viscosity Properties of Potato Starch During Growth
Authors: Madsen Marianne H. , Christensen Dan H. 
Published: November 2006

AbstractViscosity properties (Brabender Amylograph) of native potato starch were analysed in relation to harvesting date and tuber size in four cultivars. The pasting temperature of the starch decreased during growth while tuber size and cultivar were of minor importance to this parameter. Peak viscosity increased significantly during growth and with increasing tuber size. The temperature at peak viscosity decreased during growth and was higher in starch from small tubers (30‐40mm) than from larger ones. Hot paste stability decreased during tuber development and was higher in starch from small tubers. There were significant differences in peak viscosity, temperature at peak viscosity and hot paste stability between starches from the four cultivars. From these results we conclude that producing potato starch qualities according to specific demands from the industry will be possible.
Structural and Chemical Properties of Native Corn Starch Granules
Authors: Sahai D. , Jackson D. S. 
Published: November 2006

AbstractNative corn starch granules were fractionated according to size and apparent density. Individual fractions were characterized by high performance size exclusion chromatography, differential scanning calorimetry, X‐ray diffraction, scanning electron microscopy and enzymatic susceptibility. Native starch granules were not homogeneous; they showed differences in solubility, enzymatic susceptibility and crystallinity. The small, less dense granules were more crystalline than the more abundant larger and denser granules. Neither the degree of solubility of each starch fraction in methyl sulfoxide (DMSO), nor its enzymatic susceptibility, was correlated with fraction crystallinity. Starch granules with different sizes or apparent densities had inherent variations in their crystallinity, which influences granule functional properties. The helical nature of amylose and amylopectin may also contribute to the functional complexity and variability observed in the population of normal starch granules.
Factors Affecting the Visco‐Amylograph and Rapid Visco‐Analyzer Evaluation of the Impact of Annealing on Starch Pasting Properties
Authors: Jacobs Heidi , Eerlingen Relinde C. , Delcour Jan A. 
Published: November 2006

AbstractAnnealing affects the pasting properties of potato, pea, wheat and rice starches, as shown by both rapid visco‐analyzer and visco‐amylograph results. The evaluation of the impact of annealing on starch pasting curves not only depends on the starch source but also on the type of measuring instrument. Thus, rapid visco‐analyzer results (measured with a 40min or a 20min cycle) are comparable to viscoamylograph results (measured with a 120min cycle) for potato and rice starches but not for pea and wheat starches. The different results for the two instruments have to do with differences in heating and cooling rates, different start and end temperatures, and/or different shear and shear rate conditions.
Starch Citrate: Preparation and Ion Exchange Properties
Authors: Wing Robert E. 
Published: November 2006

AbstractStarch was allowed to react thermochemically (oven versus drum drying‐oven) with citric acid to potentially yield biodegradable products possessing high ion exchange capacity. Reaction variables studies were: starch type (amylose content 0‐70%). pH (0.5‐8.5), sodium level (0‐3 moles), citric acid level (0.1‐0.5 moles), reaction time, temperature (110‐140°C) and sodium dihydrogen phosphate catalysis. Reaction efficiencies approaching 100% were achieved,while minimizing crosslinking and maximizing carboxyl content. Carboxyl content was determined and copper binding capacity at pH 4.5 was evaluated.
Wet‐milling/Ammonia Process for the Manufacture of Wheat Starch and Gluten
Authors: Kema Ido P. , Helmens Harold J. , Steeneken Peter A. M. 
Published: November 2006

AbstractA laboratory‐scale procedure is proposed for the separation of starch and gluten from wet‐milled wheat. Our purpose was to assess the potential of wheat as a starch crop by optimising starch quality and yield. Features are the rapid steeping by mildly fracturing the wheat grains, the separation of starch from the gluten‐fibre mass in a slurry process, and the separation of fibres and gluten by reversibly dissolving the latter in dilute ammonia. This procedure affords starch with a low content of damaged granules which appears to be less dependent on wheat quality than in the conventional wheat flour process. Starch yield is similar to that of the flour process. Gluten recovered from ammonia is much stiffer than gluten from flour and its quality is somewhat lower, but it is generally suitable to increase loaf volume. Because of the low protein recovery and the use of ammonia, development into a large‐scale process is not likely.
Enzymic Hydrolysis of Starch in Agitated PEG‐Dextran Aqueous Two‐Phase System
Authors: Liakopoulou‐Kyriakides M. , Karakatsanis A. , Stamatoudis M. 
Published: November 2006

AbstractEnzymic hydrolysis of starch in PEG ‐ Dextran aqueous two‐phase system in a batch 2L reactor was studied under various conditions of temperature and agitation rates. It was found that a rotational speed of 150rpm gave the best results at 55°C as it can be judged by measurements of glucose concentration. Higher agitation rotational speed resulted in significant decrease of glucose production.
Measurement of Amylose/Amylopectin Ratio by High‐Performance Liquid Chromatography
Authors: Batey Ian L. , Curtin Barbara M. 
Published: November 2006

AbstractAmylose content has been measured by iso‐amylase digestion of starch followed by quantitation of the amounts of the higher molecular weight chains (from amylose) and the lower molecular weight chains (from amylopectin). The separatrion and quantitation has been performed by size‐exclusion high performance liquid chromatography on hydrophilic columns. Three columns were tested and an Ultrahydrogel 250 was found to provide the optimum separation. Starches of up to 30‐35 per cent amylose may be analysed in this way without the need for first removing the lipids. With starch of higher amylose content, precipitation of the amylose in the sample may occur while it is awaiting HPLC analysis. This precipitation can be prevented in starches of up to 40 per cent amylose by the use of dimethyl sulfoxide in the reaction mixture. Samples with amylose content higher than this always show some precipitation and the amylose contents obtained are similar for all starches with amylose in the range from 40 to 80 per cent, measured by iodine determination. The method gives results which are more repeatable than those obtained by spectrophotometric determination of iodine binding, and which appear to be unaffected by the lipid content of the starch.
Interaction of Two Sugary‐1 Alleles (su1 and su1st) with Sugary‐2 (su2) on Characteristics of Maize Starch
Authors: Campbell Mark R. , Kirksville  , Glover David V. 
Published: November 2006

AbstractTwo recessive alleles at the maize (Zea mays L.) sugary‐1 locus, sugary‐1 reference (su1) and sugary‐1 starchy (su1st), were examined. Kernels homozygous for the su1 allele result in a wrinkled/glassy phenotype while su1st kernels were nearly normal in appearance. Both sugary‐1 alleles, however, result in the wrinkled/glassy phenotype when in a double‐mutant combination with the recessive sugary‐2 (su2) gene. Our objectives were to investigate the interaction between su2 and the two sugary‐1 alleles (su1 and su1st) by examining starch thermal properties by Differential Scanning Calorimetry (DSC) and starch granule size using a laser‐based particle size analyzer. A dosage study was also conducted between su2 and the two sugary‐1 alleles in order to provide additional genetic information regarding these gene interactions. The double‐mutant genotypes su1st su2 and su1 su2 produced starches having low gelatinization enthalpy (ΔH) values (2.2 and 0.8J/g, respectively) compared to normal (12.1J/g), su2 (5.2J/g), su1st (10.9J/g) and su1 (9.2J/g). In contrast to previous studies based on birefringence end‐point temperature (BEPT), our DSC data demonstrated that su2 rather than su1 is epistatic with respect to gelatinization temperature. Dosage studies revealed that gelatinization onset (To), peak (Tp) and ΔH decreased upon increasing doses of the recessive su2 allele. A similar dosage effect for su2 was observed in a su1 and su1st background. A dosage effect was also seen for su1 on the ΔH value when the su2 gene was homozygous. No significant dosage effect occurred with respect to starch granule diameter mean or mode. A trend was observed, however, in which a slight increase in starch granule mean and mode was associated with increasing doses of the su1 allele.
Effects of High Pressures Treatment on Starches
Authors: Stute R. , Heilbronn  , Klingler R. W. , Boguslawski S. , Eshtiaghi M. N. , Knorr D. 
Published: November 2006

AbstractThe effects of ultra‐high pressure (UHP) on 25 starches were characterized via microscopy and DSC. Furthermore, the swelling behaviour, digestibility, paste viscosity and gel formation was determined. With few exceptions B‐starches were shown to be more pressure resistant than A‐ and C‐type starches. The pressure range in which the gelatinization occurs is typical for the corresponding starch. Only some starches (e.g. waxy corn starch) show the extensive swelling and almost complete desintegration of the granules, which usually is observed after a heat gelatinization. Typical for a UHP‐gelatinization is, that most starches show very little swelling and maintain their granular character. These starches develope very little viscosity at normal paste concentrations and form pastes of smooth texture, resp. rigid gels at concentrations above 15%.Due to the limited swelling without any resp. very little solubilization of the amylose obviously the retrogradation occurs within the granules, which probably is a further reason for the quite different paste and gel properties of UHP‐gelatinized starches in comparison to heat gelatinized ones.
Molecular Origin for the Thermal Stability of Waxy‐rice (Kogane) Starch
Authors: Tako Masakuni 
Published: November 2006

AbstractThe non‐Newtonian behavior and dynamic viscoelasticity of waxyrice starch (Kogane) in aqueous solution were investigated. The flow curves, at 25°C, of starch showed plastic behavior at various concentrations. The viscosity increased a little with increase in temperature up to 5 or 10°C, then it stayed at a constant value with further increase of the temperature. The dynamic viscoelasticity showed very large values and stayed constant during increase of the temperature at various concentrations. The dynamic modulus decreased a little upon addition of urea (4.0M) and in 85% DMSO during increase in the temperature. The dynamic modulus, however, showed very low value in 0.10N NaOH solution. Intramolecular associations of waxy‐rice starch molecules might play a dominant role in the thermal stability for viscosity and dynamic viscoelasticity in aqueous solution.
Non‐volatile Reaction Products by Heat‐induced Degradation of α‐Glucans. Part I: Analysis of Oligomeric Maltodextrins and Anhydrosugars
Authors: Kroh Lothar W. , Jalyschko Walentina , Häseler Jörg 
Published: November 2006

AbstractThe non‐volatile reaction products of the thermolysis of maltodextrines and soluble starch in a closed system at 180°C are analysed and are compared with those of the thermolysis of D‐glucose and 1,6‐anhydro‐β‐D‐glucose. Without derivatization the methods of AMD/HPTLC and HPAEC/PAD are suitable for the quantitative determination of mono‐ and oligomeric saccharides. On the reaction conditions used the thermolysis/hydrothermolysis of polymeric α‐glucanes first leads to the formation of D‐glucose and predominant to 1,4‐linked maltooligosaccharides. These intermediates undergo further reactions such as hydrothermolysis, transglycosylation, dehydration, and isomerisation. As a result of these reactions non‐volatile degradation products with sugar structure such as monomeric sugars (D‐glucose), anhydrosaccharides, fructose containing sugars and short chain, partly branched, maltodextrines are formed. These reaction products can act as starting material for non‐enzymatic browning reactions and produce either typical caramelisation products, connected with changes of the sugar structure, or Maillard‐reaction products in the presence of amino compounds.
Staling in Starch Breads: The Effect of Antistaling α‐Amylase
Authors: Morgan Keith R. , Hutt Lower , Gerrard Juliett , Every Dale , Ross Marcela , Gilpin Margy 
Published: November 2006

AbstractA novel starch bread that contained no gluten was found to firm at a rate comparable to a normal standard bread made from wheat flour. Treatment of both the starch and the standard bread with Novamyl, an antistaling enzyme mix, inhibited firming. 13C CP/MAS NMR studies showed that the decreased firming of the Novamyl‐treated starch bread was correlated with decreased starch retrogradation. For the Novamyl‐treated bread the increase in retrograded starch over six days following baking was about 11% compared to an increase of over 200% for the untreated bread. These results suggests that starch retrogradation is sufficient to cause bread firming.
Purification and Characterization of an Oligo‐1,6‐glucosidase from the Caldoactive Thermophile Bacillus caldotenax
Authors: Suzuki Y. , Sugita N. , Kishimoto T. 
Published: November 2006

AbstractAn oligo‐1,6‐glucosidase (dextrin 6‐α‐D‐glucanhydrolase, EC 3.2.1.10) of the caldoactive thermophile Bacillus caldotenax KP 1213 (YT‐G, DSM406) was purified to homogeneity. Its relative molecular weight, Stokes radius, sedimentation coefficient at 20°C in water, molar absorption coefficient at 280nm and pH 6.8, and isoelectric point were estimated to be 64,000, 3.3nm, 4.8S, 122,000M−1cm−1, and 4.9, respectively. The enzyme N‐terminal sequence of twenty residues was determined to be Met1‐Glu‐Trp‐Ala‐Trp‐Lys‐Glu‐Ala‐Val‐Val‐Tyr‐Gln‐Ile‐Tyr‐Pro‐Arg‐Met‐Phe‐Tyr20. The enzyme shared its antigenic groups in part with the homologue from Bacillus thermoglucosidasius KP1006 (DSM2542, obligate thermophile). The B. caldotenax enzyme was most active at 70°C and at pH 6.0–6.8. The best substrate for the enzyme was isomaltotriose of naturally‐occurring oligo‐ and polysaccharides tested. The enzyme half‐life at pH 6.8 was 10min at 75°C. The enzyme (Pro, 5.93mol%) fairly matched with a positive relationship between the thermostability of its six bacillary counterparts and their proline mol% contents. This relationship has been found to hold for sixteen bacterial enzymes from other four different groups (α‐glucosidases, pullulanases and 3‐isopropylmalate dehydrogenases).