bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Differential Scanning Calorimetry to Amaranth Starch Gelatinization – Influence of Water, Solutes and Annealing
Authors: Paredes‐Lopez O. , Hernández‐Löpez D. 
Published: November 2006

AbstractGelatinization phenomena of amaranth starch were investigated using differential scanning calorimetry. Slight variations in onset (To) and peak (Tpl) temperatures were observed at moisture contents over 0.48 g water/g total. However, completion temperature (Tc) increased significantly. The intermediate transition temperature (Tp2) appeared at 0.61 g water/g total and below. The degree of gelatinization decreased by decreasing the moisture content. The three transition temperatures (To. Tpl and Tc) were increased and gelatinization delayed as the concentration of sucrose was enhanced. The three latter transition temperatures tended to increase as the sodium chloride was raised to 0.066 g/g total, but further increases in salt reduced significantly these temperatures. The gelatinization was delayed by increasing the salt concentration. After annealing for 12 h at 25 to 65°C, starch samples exhibited higher To and Tpl values, and narrowed gelatinization ranges. The degree of gelatinization augmented up to the annealing temperature of 55ºC and significantly decreased thereafter.
Compounding of Thermoplastic Starch with Twin‐screw Extruders
Authors: Wiedmann Werner , Strobel Edgar 
Published: November 2006

AbstractThe compounding of thermoplastic starch can be regarded as a combined process consisting of extrusion cooking and plastic compounding. The quality of the product is determined largely by the degree of mechanical shear, temperature and water content. These parameters can be influenced both by the machine system and the various components of a machine. These include infinitely adjustable throttle systems and continuous condensation and evaporation equipment. On account of the fact that the starch pellets are sometimes soluble in water, the type of pelletizing is also very important. A product quality which has been optimized can be reproduced every day by means of automatic systems. Some examples of on‐line quality control systems are shown.
Morphological Study of Products Containing β‐Cyclodextrin
Authors: Hódi K. , Tasić Lj. , Kata M. , Selmeczi B. , Jovanović M. , Djurić Z. 
Published: November 2006

Abstractβ‐Cyclodextrin (β‐CD) has been applied in various fields of drug formulation. Its presence in powder Paracetamol (PAR) products prepared with different methods (kneading and spray drying) changes the morphology of original drug. The product made by spray drying has nearly isodimensional spherical particles, and potentially better flowability than the kneaded product. Spray drying of PAR product without β‐CD shows similar morphology like a product with β‐CD, but the particles show a greater inclination to adhesion. The results were obtained by electron microscopic study.
Annealing of Starch at an Intermediate Water Content
Authors: Larsson Ingela , Eliasson Ann‐Charlotte 
Published: November 2006

AbstractThe effect of annealing on starch gelatinization behaviour has earlier been described in the literature. The starch: water ratio in these studies have been either very low or very high. In this work the gelatinization behaviour has been studied both with time and temperature at an intermediate starch/water ratio (1:1) by differential scanning calorimetry. Starches from maize, waxy‐maize, wheat and potato have been compared. This investigation shows that annealing causes an increase of To and Tm, a narrowing of the gelatinization temperature interval, and a change of the shape of the endotherm can also be observed. The annealing time has to be more than 6 h to induce these changes.
Verarbeitung von Kartoffelstärke auf Kunststoff‐Verarbeitungsmaschinen
Authors: Potente Helmut , Schöppner Volker , Rücker Andreas 
Published: November 2006

AbstractStärke als makromolekular aufgebauter organischer Werkstoff besitzt viele Eigenschaften, die mit herkömmlichen Kunststoffen vergleichbar sind. Dadurch ist es möglich. die Stärke auf konventionellen Kunst;stoffverarbeitungsmaschinen mit denselben Verfahren wie die synthetischen Polymere zu Produkten zu verarbeiten. Unter Zugabe von Weichmachern ist native Kartoffelstärke auf verschiedenen Extrudern zu Granulat und Folie weiterverarbeitet worden. Das Granulat diente als Ausgangsmaterial für Versuche zur Herstellung einfacher Formkörper aus Stärke auf einer Spritzgußmaschinen. Die mechanischen Kennwerte der erstellten Proben lagen auf einem zufriedenstellenden Niveau. Durch die Eignung der weit verbreiteten Schneckenmaschinen zur Stärkeverarbeitung ist es bei genauer Kenntnis der erforderlichen Verfahren ohne umfangreiche Anlageinvestitionen möglich, für Spezialanwendungen Kunststoffe durch Stärkeprodukte zu substituieren.
Use of a Twin‐Screw Extruder as a Chemical Reactor for Starch Cationization
Authors: Valle Guy Della , Colonna Paul , Tayeb Jean 
Published: November 2006

AbstractThe objective of this work was to study the obtaining of cationic starch by using a pilot scale twin‐screw extruder Clextral BC45 as a chemical reactor. The reagent was 3‐chloro 2‐hydroxypropyltrimethyl ammonium chloride (CHPTMA) and catalyst was sodium hydroxide (NaOH). In a first set of experiments extruded starch gave higher chemical efficiencies than native starch (+15%) both being fed at the same location of the barrel. Influence of extrusion conditions on reaction kinetics was studied starting from extruded starch in order to optimize the reaction without interfering with starch melting phenomenon. In a second set of experiments, a special screw design was implemented in order to obtain a homogeneous starch molten phase in a first stage, and to achieve starch modification in a second stage. Changes of reacting conditions were performed through the modification of reagent quantities and molar ratios related to starch and NaOH, location of reagent injection, temperature of reaction and Specific Mechanical Energy input. Samples were evaluated through their degree of substitution (final DS < 0,09); their homogeneity and rheological behavior were studied by ion exchange chromatography and Brabender viscoamylograph. resp., Reaction efficiency was computed to optimize the process, leading to values up to 82%. Extruded samples were then compared to commercial cationic starches.
Purification and Characterization of the Commercialized, Cloned Bacillus megaterium α‐Amylase. Part II: Transferase Properties
Authors: Brumm P. J. , Hebeda R. E. , Teague W. M. 
Published: November 2006

AbstractUsing an assay procedure based on reduction of iodine binding to starch. Bacillus megaterium, α‐amylase (BMA) demonstrated transferase activity using a wide range of acceptors. The enzyme had an absolute requirement for glucose or glucosides for acceptor molecules. Maltose acted as a transferase acceptor at low concentrations and as an inhibitor of starch hydrolysis at high concentrations. Kinetic analysis indicated that, in the presence of a suitable acceptor, the mechanism of starch hydrolysis is Ping Pong Bi Bi. The products of the transferase reaction have been determined using p‐nitro‐α‐D‐glucopyranoside as acceptor combined with a novel HPLC‐based system for product detection.
Qualitative and Quantitative Determination of Starch by a Colorimetric Method
Authors: Magel Elisabeth 
Published: November 2006

AbstractA method for the qualitative and quantitative determination of low amounts of starch and its components, amylose and amylopectin, was worked out. It combines the extraction of starch with HCI, staining with KJ/J2 and measurement of the absorbancies at two wavelengths, 605 and 530 nm, the absorption maxima of amylose and amylopectin, respectively. The determination of the amylose fraction and the quantification of the starch were done according to two evaluated equations. Phenolic substances did not influence the method. The method proved to be useful for sensitive starch determination and characterisation in plant material.
Rapid Quantitative Measurement of Extrusion‐Induced Starch Fragmentation by Automated Gel Permeation Chromatography
Authors: Wasserman Bruce P. , Brunswick New , Timpa Judy D. 
Published: November 2006

AbstractGel permeation chromatography with application of the universal calibration concept was found to be a rapid and effective method for quantification of extrusion‐induced starch fragmentation. This method (Timpa. J.D., J. Agr. Food Chem. 39 (1991), 270–275) employs dimethyl acetamide (DMAC) with lithium chloride to solubilize samples and automated gel permeation chromatography for fractionation. Instrumentation was equipped with a viscometer and refractometer, data was interpreted by application of the universal calibration concept. These results confirm that the largest starch molecules in corn meal (107 to 108 Daltons) were slightly prone to fragmentation. Fragments produced were primarily in the weight range of 104–107 Daltons. In addition, some smaller fragments (ranging between 5,000 and 7.500) were also generated by extrusion.
Molecular Weight Patterns of Nägeli Amylodextrins
Authors: Jackson David S. , Waniska Ralph D. , Rooney Lloyd W. 
Published: November 2006

AbstractThis research was designed to assess the utility of a four‐column high performance size‐exclusion chromatography (HPSEC) system to characterize starch‐based carbohydrates of different sizes. Corn starches with varying amounts of amylose were treated with 16% sulfuric acid to create Nägeli amylodextrins. During treatment, sub‐samples were taken at various intervals from 0–100 days. The washed, dried sub‐samples were chromatographically analyzed using four Shodex lonpak columns linked in series. Chromatograms showed the progressive depolymerization of starch. Pullulan molecular weight standards were used to estimate amylodextrin molecular weights (MW). Number‐average MWs of amylodextrins decreased as the original starches' amylopectin content decreased. A single HPSEC system can be effectively used to characterize carbohydrates ranging in size from starch to amylodextrins; and to monitor the acid (or enzyme) depolymerization of starches.
Production of Cationic Starch Ethers Using an Improved Dry Process
Authors: Hellwig Georg , Bischoff Dietmar , Rubo Andreas 
Published: November 2006

AbstractCationic starch ethers have been established as additives in the paper industry for many years. A number of production processes are known and documented in numerous patents and articles. Whereas in the past starches were predominantly etherified in aqueous suspension, a trend has lately been observed towards a “dry” cationisation. Apart from the commercial aspects, the advantages of a “dry” reaction control lie in the ecological sphere as well. The advantages of the dry process for producing cationic starch ethers will be discussed here and compared with the “slurry” process. In so doing, particular attention will be paid to a dry process developed by our company since it is gaining nowadays more and more commercial relevance.
Production of Starch Saccharifying Enzyme (Glucoamylase) in Solid Cultures
Authors: Pandey Ashok 
Published: November 2006

AbstractA laboratory process was established for the production of glucoamylase (amyloglucosidase) enzyme by Aspergillus niger (RRL isolate), using wheat bran of mixed particle size as main carbon source in solid cultures. The experimental studies were carried out in 500 ml conical flasks and subsequently in tray fermenters in static conditions. Experiments were conducted to monitor the impact of initial moisture content of the substrate as well as the steam cooking of the substrate on different atmospheric pressure on the productivity of the enzyme. An initial moisture level of 50–55% was found optimum for glucoamylase production when fermentation was carried out for 96h. Cooking of substrate at 1056 kg/cm2 under steam for 30 min gave most desirable qualities in substrate.
Herstellung von Stärkederivaten durch Heißextrusion
Authors: Narkrugsa W. , Berghofer E. , Camargo L. C. A. 
Published: November 2006

AbstractEs wurde die Möglichkeiten untersucht, das Verfahren der Heißextrusion unter Verwendung eines konischen, gegenläufigen Doppelschneckenextruders zur Herstellung von Stärkederivaten einzusetzen. Als Rohstoffe wurden neben Mais‐ und Kartoffelstärke auch Maisgrieß verwendet. Als Derivatisierungsreagenzien wurden Citronensäure, Natriumtrimetaphosphat, 2,3‐Epoxypropyl‐trimethyl‐ammoniumchlorid und 3‐Clor‐2‐hydroxypropyl‐trimethyl‐ammoniumchlorid getestet.Mit allen Reagenzien konnte eine Derivatisierung sämtlicher eingesetzter Rohstoffe erhalten werden.Bei den Citratstärkederivaten wurden Reagenzienausbeuten zwischen 60 bis 70% erreicht, die durch eine nachträgliche Hitzebehandlung nach der Extrusion auf etwa 68 bis 77% gesteigert werden konnten. Durch diese nachträgliche Hitzebehandlung wurde weiters eine enorme Steigerung der Brabender‐Viskositätswerte erreicht und die Scherstabilität und Gefrier‐Tau‐Stabilität teilweise ebenfalls verbessert. Bei den Phospatstärkederivaten wurden Umsetzungsraten von etwa 30% gefunden. Diese Werte sind mit denen anderer Arbeiten vergleichbar. Durch eine nachträgliche Hitzebehandlung konnte auch bei diesen Derivaten eine weitere Steigerung bis 35% erzielt werden. Die Verbesserung der funktionellen Eigenschaften durch die Derivatisierung war hier ebenfalls zu beobachten, allerdings nicht in dem Ausmaß wie bei den Citratstärkederivaten. Die Herstellung von Kationenstärken durch Heißextrusion war ebenfalls ohne Probleme durchzuführen. Es wurden etwa 50 bis 60% der jeweils eingesetzten Reagenzien veräthert. Diese Werte steigen bei einer nachträglichen Hitzebehandlung auf etwa 65 bis 75% an. Damit sind die Ausbeuten durchaus mit der konventionellen Herstellungsweise vergleichbar.
Characterization of Internal and Surface Lipids of Oat Starches from Two Isolation Processes
Authors: Liukkonen Kirsi , Laakso Simon 
Published: November 2006

AbstractOat starches representing two different isolation methods were studied for lipid contents and compositions. One of the starch isolation methods utilized water and the other slightly alkaline solution. The internal lipids were practically identical in both starches. However, starch from the alkaline method contained 21% less non‐starch lipids as total fatty acids, 63% less Kjeldahl nitrogen, and the content of non‐starch free fatty acids was low. Instead, starch from the water method contained almost three fold higher amounts of free fatty acids which contributed up to 49% of non‐starch lipids. Therefore, it was concluded that isolation of starch under alkaline conditions both reduces the content of non‐starch lipids and maintains a better composition in the residual starch lipids.
Rigid Polyurethane Foam Prepared from Extruded Starch‐Derived Glycol Glucosides as Chemical Intermediates
Authors: Carr Merle E. , Cunningham Raymond L. 
Published: November 2006

AbstractStarch‐derived glycol glucosides were prepared by a continuous, twin‐screw extrusion process; reacted with propylene oxide; and evaluated as the polyether polyol (PP) in rigid polyurethane (RPU) foam. Cornstarch with 10% moisture, ethylene glycol (EG), and sulfuric acid as the catalyst were reacted at 160°C in the extruder, using 4 moles EG/mole starch anhydroglucose unit (AGU). After removing unreacted EG from the extrudate by vacuum distillation, the crude mixture of products, which contained at least 85% anomeric glucosides, was reacted with propylene oxide to form the PP with a hydroxyl number of 470. The PP was then deionized and reacted with a polymeric diisocyanate, using a conventional type of formulation and pour‐in‐place procedure. The same formulation and procedure were used to prepare RPU foam from a commercial methyl glucoside PP (hydroxyl number 443) for comparison.The insulating capacity, compressive strength, and dimensional stability properties of the foam with the experimental PP were at least as good as the foam with the commercial PP. This study demonstrates, for the first time, that the starch‐derived glycol glucosides prepared by reactive extrusion processing are suitable chemical intermediates for the preparation of RPU foams with good properties. Also the study suggests that other types of starch‐derived glucosides could be prepared by reactive extrusion processing for potential uses in foams, alkyd resins, surfactants and other products.
Study on Specific Modification of Glucosyl Cyclodextrins
Authors: Hisamatsu Makato , Yamada Tetsuya , Nakashima Kouchi , Tabata Kengo 
Published: November 2006

AbstractThe time courses of the periodate oxidation of glucosyl cyclodextrins complexed with organic solvents indicated the preferential oxidation of glucosyl residues on side chains, and the modified cyclodextrins could be purified by using a reversed phase column. HPLC and 13C‐NMR analyses ensured that the modified cyclodextrins were cyclodextrins having aldehyde residues on their side chains (aldehyde cyclodextrins).
Preparation and Application of Starch Graft Poly(vinyl) Copolymers as Paper Coating Adhesives
Authors: Carr M. E. 
Published: November 2006

AbstractA series of starch graft copolymers were prepared from commercial cornstarch products and vinyl monomers and were evaluated as adhesives in pigmented paper coatings. Hypochlorite oxidized (HO), acid modified (AM), and hydroxyethlated acid modified (HEAM) starches were reacted separately with acrylamide (AAm), acrylic acid (AAc), and acrilonitrile (AN) using ceric ammonium nitrate as the polymerization initiator to yield copolymers containing 2–45% synthetic polymer. Pigmented coating mixtures with 6–14 parts co‐polymer/100 parts clay and 40–50% total solids were prepared and applied on one side of the paper stock using a hand‐drawn doctor blade. Viscosities, adhesive strength, and wet‐rub resistance of the coating adhesives and mixtures were determined. Adhesive strength of starch graft polyacrylamide (S‐g‐PAAm) copolymers containing as little as 12% PAAm was considerably superior to the commercial starches as paper coating adhesives. Adhesive strength of S‐g‐PAAc copolymers was similar to that of the HO and HEAM commercial starches, whereas adhesive strength of the S‐g‐PAN copolymers was poor. Copolymers that were prepared from the HO starch were slightly superior to those prepared from the AM and HEAM starches. Wet‐rub resistance of the pigmented copolymer coatings was not improved over that of the coatings containing the commercial starches.
Production and Characterization of Cyclodextrin Glycosyltransferase from Bacillus lentus
Authors: Sabioni Jose G. , Park Yong K. 
Published: November 2006

AbstractA new alkalophilic Bacillus. which produced exceptionally high activity of cyclodextrin glycosyltransferase, was isolated from soil. This strain of Bacillus was identified as Bacillus lentus. The enzyme was purified and characterized. It was found that optimum pH and temperature for cyclodextrin forming activity were 6.5–8.5 and 45–55°C. Thermal stability of the enzyme was remarkably increased by the addition of calcium ions. The maximum conversion of starch to cyclodextrin by the enzyme was 65%. The cyclodextrins formed after 24 h of enzymatic reaction consisted of α‐. β‐ and ‐y‐cyclodextrins in proportion of 1:67 : 1.6.
On the Mechanical Properties of Native Starch Granules
Authors: Schroeter Johannes , Hobelsberger Marco 
Published: November 2006

AbstractAs a fundamental prerequisite for starch based material development, we set up a method to determine mechanical properties of native starch granules. Instead of measuring tiny single granules, we developed an indirect procedure. It relies on a verified composite material theory and simple tensile tests with starch filled plastics. Resulting data for native potato starch granules: elastic modulus 2.7 GPa, tensile strength 60 MPa, indentation hardness 113 N/mm2. These data are similar to those of rigid thermoplastics.
The Modification of Starch by High Pressure. Part II: Compression of Starch with Additives
Authors: Kudla Ewa , Tomasik Piotr 
Published: November 2006

AbstractDry and wet starch containing 2, 5, 10, 15, 18, 20 and 22% of humidity was compressed under 0.8, 1.0 and 1.2 × 109 Pa. Also starch containing chlorides of sodium, calcium barium, tin (II), zinc, copper (II), cobalt(II) and iron (III) as well as molecular iodine and all sodium fluoride, bromide, iodide, phosphate, sulfate and rhodanide was similarly compressed. It was found that humidity accelerates the destruction of starch matrix. Among mineral additives only cobaltous and ferric chlorides as well as iodine corraborate with high pressure in the deterioration of starch matrix.
A Pulsed NMR Method for the Study of Starch Retrogradation
Authors: Teo C. H. , Seow C. C. 
Published: November 2006

AbstractA rapid and non‐destructive pulsed NMR method of monitoring starch retrogradation was developed based on the principle that the signals from protons in the “solid‐like” and liquid components in a system decay at significantly different rates following a 90° radio‐frequency pulse. As molecular association or recrystallization proceeds during aging of a starch gel, the proportion of the “solid‐like” component in the system increases. The resulting decrease in segmental mobility of the starch chains causes a decrease in the signal from the liquid component, but a concomitant increase in the signal attributed to protons in the “solid‐like” fraction. The method was applied to study the retrogradation tendency of starches from different botanical sources.
Effect of Molar Substitution (MS) on Calcium Binding by Hydroxypropyl Rice Starches
Authors: Islam M. Nurul , Azemi B. M. N. Mohd. 
Published: November 2006

AbstractUnisolated rice starch was obtained by wet milling of broken milled rice grains. Hydroxypropyl rice starches of different level of molar substitution (MS) were prepared and characterized. Both native and modified starches were treated with calcium carbonate at various calcium: starch ratios. Binding was markedly influenced by the calcium concentration in the reaction mixtures. Native starch binds less calcium than modified starch. Ability to bind calcium decreased with increasing calcium concentration in both native and modified starches. A parallel increased in calcium binding was observed as MS increased to the value of 0.09 and thereafter reversed. Increased level of substitution depressed the optical rotation and electrical conductivity of starch‐calcium complex.
Microstructural and Physicochemical Properties of Oxidized Potato Starch for Paper Coating
Authors: Autio Karin , Suortti Tapani , Hamunen Antti , Poutanen Kaisa 
Published: November 2006

AbstractHeat‐induced structural changes were examined for a series of potato starches differing in degree of oxidation and prepared as 25 and 35% dispersions. The molecular weight of amylopectin decreased markedly with the degree of oxidation. Microstructural studies revealed that all oxidized potato starch dispersions heated to 90deg;C contained whole granules. The least oxidized potato starch (Raisamyl 316) paste contained large numbers of swollen granules filled with dissolved amylose. In the more oxidized potato starch dispersions, both amylopectin and amylose were solubilized within the granule. Mixing of the amylose and amylopectin occurred and amylose‐ and amylopectin‐rich domains could be seen inside the granule. At 35% concentration all starches studied formed a gel during cooling (from 90 to 30deg;C). The lower the degree of oxidation, the higher the gelling temperature. Raisamyl 310 formed the firmest gel. The gel formation of most oxidized potato starches was weak. Raising the heating temperature from 90 to 120deg;C, in combination with shearing, delayed the gelation.