bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Study of Melting Temperature and Enthalpy of Starch from Rice, Barley, Wheat, Foxtail‐ and Proso‐millets
Authors: Fujita S. , Fujiyama G. 
Published: November 2006

AbstractEndosperm starch granules prepared from rice, barley, wheat, foxtail‐and proso‐millets were analyzed by Differential Scanning Calorimetry (DSC) and the relationship between melting temperature and enthalpy for starch gelatinization was discussed. Peak temperature for gelatinization (Tp) ranged from 57 to 80°C and enthalpy from 6.4 to 15.6 J/g. Starch from rice, barley, foxtail‐ and proso‐millets which has a waxy phenotype, has shown a correlation between Tp and enthalpy, while that of wheat has not.
Chemical Factors Affecting Acetylation of Cassava Starch
Authors: Aiyeleye F. B. , Akingbala J. O. , Oguntimein G. B. 
Published: November 2006

AbstractThe effects of liquid‐starch ratio, concentration of sulphuric acid, and glacial acetic acid on the degree of substitution of acetylated cassava starch were investigated. The optimum liquid starch ratio was 2.5. The degree of substitution increased rapidly with sulphuric acid concentration up to 0.36m at a liquor‐starch ratio of 2.5. The optimum concentration of glacial acetic acid at liquor‐starch ratio of 2.5 and 0.64m sulphuric acid was 13.9m with a reaction efficiency of 88%. The acetylated cassava starch was more soluble than the native cassava starch.
Herstellung und thermische Eigenschaften hochsubstituierter Benzylstärken
Authors: Braun Dietrich , Stipp Gabriele 
Published: November 2006

AbstractStärke kann in alkalischem Medium mit Benzylchlorid zu Benzylstärken mit unterschiedlichen Substitutionsgraden umgesetzt werden. In wäßrig‐alkalischem Medium werden Benzylstärken mit einem maximalen Substitutionsgrad von 0,9 erhalten. Im wasserfreien Medium erzielt man höhere Substitutionsgrade. Die höchsten Substitutionsgrade (2,9–3,0) werden bei Umsetzungen von in Dimethylsulfoxid (DMSO) gelöster Stärke mit festem Natriumhydroxid und mit Benzylchlorid erhalten. Niedrigere Substitutionsgrade (max. 2,7–2,8) ergeben sich in homogenem Medium, wenn eine Lösung aus Natriumhydrid/DMSO mit in DMSO gelöster Stärke mit Benzylchlorid umgesetzt wird. Durch Herabsetzen der Benzylchloridkonzentration können hierbei gezielt Benzylstärken mit niedrigeren Substitutionsgraden erhalten werden.Die Glastemperaturen von Benzylstärken mit Substitutionsgraden über 2,5 liegen bei ca. 45–55°C. Mit abnehmendem Substitutionsgrad wird ein Anstieg der Glastemperatur bis über 70°C beobachtet. Der Schmelzbereich der Benzylstärken liegt zwischen 150‐180°C; dabei beginnt allerdings auch bereits die Zersetzung.
Enzymatic Degradation of Polydextrose® and of a High‐Molecular Polydextrose Fraction
Authors: Richter Manfred , Grossklaus Rolf , Boczek Peter 
Published: November 2006

AbstractThe enzymatic degradation of the alternative carbohydrate, Polydextrose® (PD) and of a high‐molecular fraction of PD (PD‐D) obtained by dialysis was studied. The reaction products were measured by thin‐layer chromatography (TLC) and high‐pressure liquid chromatography (HPLC). Taking into account the experimentally determined extraneous activity of enzymes, a digestibility of 22.5% was measured under in vitro conditions. This digestibility was brought about primarily by glucoamylase activity. The results also served to demonstrate contemporary concepts of the structure of PD which, instead of an arbitrary one, proposes a defined arrangement of α‐glucosidic 1,4 and 1,6 bonds within structurally different segments of the PD molecule. It has been documented by in vivo studies that the digestibility of PD in the small intestine is obviously based on the interaction of a number of substrates and enzymes and can be influenced by the composition of the diet.
Automatisierte enzymatische Bestimmung von Glucose, Maltose und Stärke auf Mikrotiterplatten
Authors: Richter M. , Tietz U. J. 
Published: November 2006

AbstractEs wird eine automatisierte Methode zur Zucker‐ und Stärkebestimmung beschrieben. Die Eliminierung methodisch bedingter Fehler bei der optischen Vermessung der Mikrotiterplatte sowie die Auswertung der 96 Rohdaten erfolgt mit dem Softwareprogramm „LBR1993”︁. Die Analytik basiert auf einer 10minütigen Substrathydrolyse durch Glucoamylase bei Zimmertemperatur und Bestimmung der Glucose mit der GOD‐PAP‐Methode. Eine Wiederfindungsrate größer 99% sowohl für Mais‐ als auch für Kartoffelstärke wird erreicht, wenn die Stärke bei 100°C durch α‐Amylase in α‐Dextrine umgewandelt und diese nachfolgend mit 8,88 g Glucoamylase/g Substrat verzuckert werden. Bei Kartoffelstärke führt das Dispergieren in 1 N Natronlauge bei Zimmertemperatur zu einer Wiederfindungsrate von 93%. Das Erhitzen (60°C) in 0.5 N Natronlauge (AFNOR‐Methode) ist zur Analyse von Zuckern sowie bestimmter Stärkearten ungeeignet.
Viscosity Behaviour of the Mucilage Extracted from Ruredzo (Dicerocaryum zanguebarium)
Authors: Benhura Mudadi A. N. , Marume Maud 
Published: November 2006

AbstractThe concentration of metal ions in the mucilage that is extracted from Ruredzo (Dicerocaryum zanguebarium) was determined by atomic absorption spectroscopy. Calcium, magnesium, potassium, iron, copper, lead and zinc were found to occur in concentrations ranging from 0.01 ppm for lead to 15 ppm for calcium. Cations were removed from solutions of the mucilage using Dowex 50W‐X12 resin and the viscosity of the decationized mucilage studied. Addition of CaCl2, NaCl and sucrose decreased the viscosity of the decationized mucilage but addition of sucrose resulted in an increase in viscosity. The effect of incubating the mucilage at various temperatures for up to 30 min before measuring the viscosity at 25°C was investigated. No change in viscosity was observed for samples incubated at 40°C and 60°C. 80°C incubation resulted in reduced viscosity. Solutions of the decationized mucilage exhibited maximum viscosity at pH 5.
Solubility Pattern and Recrystallization Behavior of Oat Starch
Authors: Shamekh S. , Forssell P. , Poutanen K. 
Published: November 2006

AbstractThe oat starch studied had a lipid content of 1,3% and amylose content of 29%. Based on the colorimetric assay, only 15% of the starch leached out from the native granules at 95°C was amylose, whereas 85% of the starch leached from the defatted granules was amylose. The solubilized amylopectin‐type material of native oat starch was of clearly lower molecular weight than most of the amylopectin in the original starch. The amylopectin recrystallization enthalpy of 50% native oat starch dispersion Id after gelatinization was 2J/g and that of defatted oat starch was 4J/g.
Comparative Study about Commercially Available Starches for High Shear and High Temperature Applications in Foods
Authors: Kuhn Klaus , Schlauch Sandra 
Published: November 2006

AbstractThe shear stability and heat resistence of hot starch pastes of more than 30 different commercially available starches has been evaluated. The shear experiments were carried out by a high shear system in the BOHLIN CS rheometer and in comparison outside the rheometer by treatment with a high shear mixer. Native starches are very sensitive against shear stress. The viscosity of non cross‐linked chemically modified starches was also decreased. It was not possible to find a correlation between the dependence of shear influence on the viscosity and the type of chemical modification. The high temperature measurements (up to 140°C) in principle showed 3 categories of viscosity development. Firstly, a category, where the viscosity breaks down, secondly, a category where the viscosity remains constant and a last category where the viscosity will be built up during the heating period. No direct dependence on the chemical modification could be observed with respect to the viscosity development.
Physicochemical Properties of Jacatupé (Pachyrhizus erosus L. Urban) Starch
Authors: De A. Mélo Enayde , Krieger Nádia , Stamford Tâania Lúcia Montenegro 
Published: November 2006

AbstractThe physicochemical properties of the starch extracted from Jacatupé (Pachyrhizus erosus L. Urban) were studied. The small‐sized granules (approximately <10μm long) present varying geometric forms: round, cupoliform and convex‐biconcave shaped granules predominate. The amylose content is 23% and crystallinity pattern is type A. Values for intrinsic viscosity and absolute density are similar to those for cassava (Manihot utilissima) starch. Extraction and purification procedures are easy to perform. Root productivity is high (50t/hectare). According to these results, Jacatupé roots can be considered a new alternative source for starch production.
Gelation of Amylopectin without Long Range Order
Authors: Cameron Ruth E. , Durrani C. Matin , Donald Athene M. 
Published: November 2006

AbstractWeak amylopectin gels have been formed directly following dissolution of waxy maize granules. Rheological characterisation of these gels has been carried out as a function of stress and frequency. The gels are visually clear and homogeneous, and environmental scanning electron microscopy shows no trace of the original granules remaining. It is postulated that the origin of the gel network lies in pairwise aggregation of outer chains of the amylopectin molecules, presumably via double helix formation. However, these pairs of chain segments do not aggregate to develop crystallinity.
A Study on Reaction Influencing Factors in Carboxymethylation of Leucaena glauca Seed Gum
Authors: Raval D. K. , Patel S. P. , Patel R. G. , Patel V. S. 
Published: November 2006

AbstractSodiummonochloroacetate and sodiumhydroxide were employed under different conditions to prepare and optimize the carboxymethyl derivative of Leucaena glauca seed gum. The effects of concentration of reactants, reaction temperature and time have been interpreted in terms of degree of carboxymethylation as well as efficiency and rate of carboxymethylation reaction. The formation of the proposed derivative has also been supported by providing infra‐red spectral characterization.
Improved Reaction Conditions for Preparation of β‐Cyclodextrin (β‐CD) from Cassava (Manihot esculenta Crantz) Starch
Authors: Raja K. C. M. , Ramakrishna S. V. 
Published: November 2006

AbstractExperimental conditions for bioconversion of starch to get higher yield of ß‐cyclodextrin using cyclodextrin glycosyl transferase (CGT‐ase) (EC 2.4.1.19) were worked out. A 5% initial starch concentration gave ß‐CD yield of 20‐28% that could be separated as ß‐CD bromobenzene complex from the reaction mixture. Addition of bromobenzene during the second phase of the reaction, i.e. CD formation phase, was found beneficial.
Starch and Amylopectin — Rheological Behavior of Gels
Authors: Bello‐Pérez L. A. , Paredes‐López O. 
Published: November 2006

AbstractRheological behavior of starch and amylopectin gels was evaluated by small amplitude oscillatory testing using the storage modulus (G′), loss modulus (G″) and the complex viscosity (n*). It was found for the three starches (normal and waxy corns, and amaranth) that at low frequency the viscous component G″ had a major contribution on the gel structure than the elastic G′ and that the complex viscosity (n*) diminished when the frequency was increased. Amaranth amylopectin showed G″ values higher than those of G′. Corn commercial and waxy corn amylopectins presented a similar behavior in the G′ values. Normal corn amylopectin gave the highest complex viscosity values.
Structure and Chemical Properties of Partially Heated Corn Starch Granules
Authors: Sahai Deepak , Jackson David S. 
Published: November 2006

AbstractPartially heated (65°C) normal dent corn starch granules (5% aqueous suspensions) were fractionated according to granule size and apparent density. The fractions obtained were individually characterized by high performance size exclusion chromatography (HPSEC), differential scanning calorimetry (DSC), X‐ray diffraction, scanning electron microscopy and enzymatic susceptibility. Heat damaged granules were concentrated in a single fraction. The heat damaged fraction was highly susceptible to degradation by amyloglucosidase. HPSEC profiles of fractions showed differences in apparent solubility of amylose and amylopectin. The heat damaged fraction showed a high temperature (85°C) gelatinization endotherm in a DSC, indicating melting of double helices, but showed a V type X‐ray diffraction pattern. Starch granules exhibited different responses to heat because of inherent heterogeneity in their native state.
Reaction of Starch and Cellulose with Products of Thermal Decomposition of Mono‐ and Disaccharides
Authors: Tomasik Piotr , Jane Jay‐Lin 
Published: November 2006

AbstractD(—)‐Fructose, dextrose and sucrose were thermally decomposed in the presence of native and pregelatinized corn starch, cellulose as well as its mixtures with native corn starch. Several products were obtained in which reactive intermediates thermally generated from lowmolecular saccharides were involved. When starch either was not gelatinized or it could not gelatinize on reaction, the preference for the formation of a physical mixture of caramel with starch and starchsugar complexes was observed. Otherwise products of substitution of starch with reactive intermediates and inclusion complexes were formed. Cellulose appeared to be more reactive. It was grafted to starch by reactive intermediates thermally generated from dextrose.
Extraction of High Amylose Starch from Wrinkled Peas
Authors: Meuser Friedrich , Pahne Norbert , Möller Matthias 
Published: November 2006

AbstractIn Europe, the extraction of starch from wrinkled peas is interesting in economic terms as it would enable a high amylose starch to be isolated from a native raw material. Extraction of starch from wrinkled peas with a high yield and purity does, however, make high demands on the mechanical processing of the raw material. For this reason, studies were carried out with the aim of developing processing parameters with which a suitable disintegration of the raw material could be achieved. This included an investigation into the influence of the way the raw material was prepared and its disintegration. Based on the results of these investigations, a process was developed in which wrinkled peas were steeped in warm water, then hulled using rubber rollers in order to separate the husks from the cotyledons. This was followed by gentle particle size reduction of the cotelydons and high‐pressure disintegration of the screened out protein/starch fraction suspended in the process water. This process enabled up to 89% of the starch present in the wrinkled peas to be extracted, with a residual protein content of around 1%, and by‐product fractions containing a high concentration of the constituent characterising them to be obtained.
Effects of Solutes on Retrogradation of Stored Starches and Amylopectins: A Calorimetric Study
Authors: Bello‐Pérez L. A. , Paredes‐López O. 
Published: November 2006

AbstractStarch and amylopectins from different sources were studied to know their calorimetric behavior when mixed with sucrose, glucose and sodium chloride to different concentrations, and stored to different times. It was found that for control samples of amaranth, waxy and normal corn starches slight changes in enthalpy values were observed. The three starches presented retrogradation endotherms, in the presence of sugars, after 2 storage weeks with low enthalpy values; these values tended to be higher by decreasing sugar concentration. The effect of sodium chloride on starch retrogadation was different to that of sugars; waxy corn starch did not show enthalpy values at all experimental conditions. theories on retarding effect of sugars have been proposed but the effect of salt on retrogradation until now is difficult to explain. Amylopectin in the presence of sucrose showed retrogradation endotherms after 3 storage weeks and with glucose after 4 weeks, except potato amylopectin which did not exhibit this trend at any tested condition. With sodium chloride all amylopectins presented retrogradation endotherms after 4 weeks. The different behavior of amylopectins with solutes could be explained by the different chain distribution in such macromolecules.
Physicochemical Changes in Cassava Starch and Flour Associated With Fermentation: Effect on Textural Properties
Authors: Numfor Festus A. , Walter William M. , Schwartz Steven J. 
Published: November 2006

AbstractPhysicochochemical changes in cassava starch and flour associated with fermentation were investigated and related to textural properties of its flour pastes. Cyanide and pH decreased, while crude protein, acidity, and apparent amylose content increased in the fermented products. Average starch granule diameter, solubility, and swelling power were depressed, while gelatinization enthalpy increased. Amylograph of starch showed increased peak visocity temperature, reduced peak, breakdown, and setback viscosities, while Texture Profile Analysis showed a decreased in hardness, cohesiveness, elasticity, and gumminess of the fermented flour paste. The altered textural properties were attributed to greater starch granule stability due to short amylose‐like fragments formed by enzymatic hydrolysis of amylopectin.
The Reactivity of Native and Autoclaved Starches from Different Origins Towards Acetylation and Cationization
Authors: Vasanthan T. , Sosulski F. W. , Hoover R. 
Published: November 2006

AbstractNative potato, waxy corn, corn, wheat, filed pea and lentil starches were autoclaved at 15 psi, 121°C for 1min. Scanning electron micrographs of the native and autoclaved starches showed no changes in granular surfaces and shapes. In all starches, the X‐ray intensities at most of the d‐spacings between 3‐18 Å increased upon autoclaving, being more pronounced in potato. The X‐ray patterns of cereals and legumes remained unchanged, while that of tuber (potato) became more cereal‐like. Differential scanning calorimetry of the starch samples revealed that autoclaving increased the gelatinization transition temperatures of wheat but decreased that of potato; the changes observed in waxy corn, corn, field pea and lentil starches were very small. The gelatinization enthalpy of all native starches decreased upon autoclaving while the percentage decrease was highly marked in potato. Image analysis of the native and autoclaved starches revealed changes in the granule size distribution patterns. Also, the population mean area of all native starch granules considerably increased upon autoclaving. Acetyl binding capacity, measured at 5% and 10% acetic anhydride addition levels, was higher in autoclaved than in native starches. Furthermore, autoclaving had no influence on starch cationization, studied at 3% and 6% reagent addition levels. The results indicated that the changes in starch molecular organization caused by autoclaving enhanced its reactivity towards acetylation but not cationization.
Effect of Shear Energy on Size Reduction of Starch Granules in Extrusion
Authors: Zheng Xiaoge , Chiang Win‐Chin , Wang Shaw S. 
Published: November 2006

AbstractThe changes of size and size distribution of starch granules under extrusion conditions have been investigated by using a single screw extruder and an optical microscope coupled with an image analysis system. The mechanical energy input and material processing time were key factors influencing the degree of starch granular size reduction. In a high shear extrusion process (T=40°C), the weight average granular size of extrudate was reduced from ˜12.4μ (raw waxy corn starch) to 1˜2μ, whereas in a low shear extrusion (T=90°C), and granular size was reduced to ˜7μ. Fine particles (±0.5μ) were observed in both extrusion processes. They were 76% (w/w) under a high shear and long processing time conditions and 5% in a low shear and short time process. During the size reduction process, the peaks of size distribution of starch granules shifted from the large size region toward the medium size region and finally to a rather narrowed peak at the small size region when extensive size reduction measures were applied. Extrusion processes can be used to reduce starch granular size effectively.
Untersuchung des Einflusses charakteristischer Merkmale von Weizenprimastärke auf deren Oxidierbarkeit mit Natriumhypochlorit
Authors: Laude Meike , Meuser Friedrich 
Published: November 2006

AbstractDie Oxidation von Weizenprimastärken mit Natriumhypochlorit in einer dreistufigen Reaktion führte in Abhängigkeit von der analytischen Zusammensetzung, Partikelgrößenverteilung und dem Raffinationsgrad der Stärken zu unterschiedlichen Oxidationsgraden. Außerdem wurde festgestellt, daß vor der Oxidation vorhandene Unterschiede in den viskosen Eigenschaften der Stärken auch nach der Oxidation noch vorkamen. Die Abhängigkeit des unter den Reaktionsbedingungen erzielten Oxidationsgrads vom Protein‐ und Fettgehalt sowie dem Median der Partikelgrößenverteilung konnte mit einer Regressionsgleichung beschrieben werden. Der Proteingehalt beeinflußte den Oxidationsgrad negativ und die Partikelgröße positiv. Alle drei Einflußgrößen überlagerten sich. Der jeweils erreichte Oxidationsgrad wurde gut mit der aufgestellten Gleichung beschrieben.
Synthesis and Physicochemical Studies of Starch‐Sulphonated Phenol Formaldehyde Cationic Exchangers
Authors: Farag S. 
Published: November 2006

AbstractA new cationic exchanger was synthesized through a complex system involving reactions of starch or modified starches, phenol and formaldehyde in presence of HCl, followed by sulphonation using sulphuric acid. Major properties of these resins including exchange capacity, swellability, solubility, ability to remove heavy metals were studied and compared with those of sulphonated phenol formaldehyde resin. This was done to signify the importance of the presence of the starch or the modified starches in the backbone of the resin. Tentative mechanisms for the reactions involved in the synthesis of such cation exchangers is also reported.
Immobilization of Aspergillus niger Mycelium on Seeds for Glucoamylase Production
Authors: Fiedurek Jan , Szczodrak Janusz 
Published: November 2006

AbstractMycelium of the glucoamylolytic mutant Aspergillus niger C‐58‐III was immobilized on wheat, rye, barley, pea, buckwheat and mustard seeds in repeated‐batch flasks. After every 24th it was possible to obtain culture broth rich in glucoamylase. The highest yield of enzyme (66.4 U × ml−1) was obtained on the mustard carrier. Immobilized cells were successfully reused with high level of enzyme formation being mantained for longer period (192h). Some of the variables influencing the enzymatic activity have been standardized. Enzyme productivity reached in immobilized cells of A. niger was 1.6‐times higher in comparison with free cells.
The Effects of Busan Preservative on Apparent Starch Purity Using the EC Ewers Method
Authors: Kennedy J. F. , Taylor D. W. , Knill C. J. 
Published: November 2006

AbstractThe effect of Busan preservative upon the starch purity values produced by the Ewers polarimetric assay was investigated. The results show that the use of a Busan blank results in a 1.2% underestimation of starch purity. If Busan effects are not compensated for, then a 0.657% underestimation of starch purity results. There is also a reduction in apparent starch purity values due to Busan reacting with some of the hydrochloric acid in the Ewers test. This portion of acid is therefore not available to react with starch in the Ewers test resulting in the loss of about 1% of acid before the test begins. This is important in an analysis where acid concentration is critical to results.