bluuebunny/crossref_metadata_2025 huggingface dataset:
Eigenschaften von Gießfilmen aus nativen und chemisch modifizierten Stärken
Authors: Funke Ulrike , Lindhauer Meinolf G.
Published: November 2006

Aus Kartoffel‐, Markerbsen‐ und Amylomaisstärke wurden Stärkeacetate und ‐hexanoate niedrigen und hohen Substitutionsgrades (DS = 0,1‐2,8) hergestellt und als Ausgangsmaterialien zur Herstellung von Gießfilmen im Labormaßstab eingesetzt. Ziel der Arbeit war es, den Einfluß der Stärkeart und der Derivatisierung auf bestimmte Filmeigenschaften, wie Zugfestigkeit und Reißdehnung sowie Wasseraufnahmen und Löslichkeiten zu untersuchen.

Aus den nicht oder nur teilweise substituierten Stärken wurden nach Zugabe von Weichmachern flexible, transparente und wasserlösliche Filme erhalten, während aus den vollständig substituierten Stärken wasserunlösliche Filme hergestellt wurden.

Der bekannte Amylosevorteil bei der Filmherstellung zeigte sich erst nach der Derivatisierung. Im Fall der Markerbsen‐ und Amylomaisstärke reichten bereits niedrige Substitutionsgrade aus, um die mechanischen Eigenschaften der Filme, sowohl die Zugfestigkeit als auch die Reißdehnung, deutlich zu verbessern.
The Relation between Calcium Sequestering Capacity and Oxidation Degree of Dicarboxy‐Starch and Dicarboxy‐Inulin
Authors: Besemer Arie C. , van Bekkum Herman
Published: November 2006

The objective of this study was to establish the relation between the calcium sequestering capacity (SC) of dicarboxy‐starch and that of dicarboxy‐inulin, and the oxidation degree of these products. An S‐type curve is obtained when plotting the SC of oxidized starch versus the degree of oxidation. By contrast the sequestering capacity of dicarboxy‐inulin increases linearly with the degree of oxidation. The difference in behaviour of these materials can be attributed to the fact that upon starch oxidation the favourable oxydiacetate structure is obtained only after substantial conversion, whereas in inulin this structure is obtained immediately and is present in each oxidized fructose unit.
Distribution of Partial Digestion Products of Hydroxypropyl Derivatives of Maize, Waxy Maize and High Amylose Maize Starches
Authors: Azemi B. M. N. Mohd. , Wootton M.
Published: November 2006

Porcine pancreatic α‐amylase digests of native and hydroxypropyl derivatives of maize (NM), waxy maize (WM) and high amylose maize starches (HA) were subjected to ethanolic fractionation into oligosaccharide and polysaccharide fractions. Both fractions of the partial digests were analysed for blue values, reducing values, total carbohydrates, average degree of polymerisation and molar substitution (MS). Distribution of hydroxypropyl groups between the fractions varied depending on starch type and level of substitution with the polysaccharide fraction being higher in MS. Blue values (BV) and average degree of polymerisation (DP) tended to decrease with digestion while reducing values (RV) increased.
Retrogradation of Potato Starch as Studied by Fourier Transform Infrared Spectroscopy
Authors: van Soest J. J. G. , De Wit D. , Tournois H. , Vliegenthart J. F. G.
Published: November 2006

Retrogradation kinetics for a potato starch‐water system (10% w/w gel) was monitored by Fourier Transform Infrared spectroscopy and compared with waxy maize starch. The spectra showed the C‐C and C‐O stretching region (1300‐800 cm−1) to be sensitive to the retrogradation process. A multi‐stage process was observed during the retrogradation of potato starch and characterized as the formation of short‐ and long‐range order. The first stage was characterized as the formation of helices and the fast formation of crystalline amylose regions. The second stage was described as the induction time for amylopectin helix aggregation. Stage three was described as the helix‐helix aggregation and the crystallization of amylopectin. The overall‐first order calculated rate constant of potato starch was (9.6±1.4) 10− 3h−1. The calculated rate constant were in agreement with the known difference in retrogradation kinetics of waxy maize and potato starch. The effects were explained by the differences in retrogradation rate of amylopectin and amylose. Potato starch consists of amylose as well as amylopectin. Whereas amylose crystallization occurs within a few hours, amylopectin crystallization is slow and takes a few weeks.
Microwaves in Physical and Chemical Modifications of Starch
Authors: Muzimbaranda C. , Tomasik P.
Published: November 2006

Maize, cassava and potato starch was modified by the low and medium low energy of microwave radiation. Plain starch undergoes dextrinization. Starch blended with TiCl4 gave gels of low viscosity. Reactions with formaldehyde as well as with acetylene gave products of enhanced viscosity.
Purification and Properties of the Raw Starch Digesting Amylase from Penicillium brunneum No. 24
Authors: Haska Nadirman , Ohta Yoshiyuki
Published: November 2006

Raw sago starch digesting amylase was obtained from Penicillium brunneum No. 24. The crude enzyme from this strain contains carboxymethylcellulase (CMC‐ase), avicelase, α‐amylase and α‐glucosidase. Affinity chromatography (α‐cyclodextrin‐Sepharose 6B) of the enzyme after ammonium sulfate fractionation, Toyopearl HW‐55F gel filtration, DEAE‐Sephadex A‐50 and DEAE‐cellulose chromatographies fractionation steps, resulted in a homogeneous glucoamylase. SDS‐polyacrylamide gel electrophoresis of purified enzyme showed a single band, and a molecular weight of 80,000 for the native glucoamylase from Penicillium brunneum No. 24 was observed. After modification of the native glucoamylase with subtilisin, the molecular weight was reduced to 76,000. It lost the ability to digest and adsorb onto raw starches. However, its ability to digest gelatinized starches was preserved.
Gelatinization and Solubility Properties of Commercial Oat Starch
Authors: Mua John‐Paul , Jackson David S.
Published: November 2006

Gelatinization and solubility characteristics of starch contribute to unique functionality in foods. Corn and oat starch viscoamylographs (35g db) showed peak viscosities of 400 and 390B.U., respectively. Oat starch had a more rapid (89.7 vs 85.6°C) and higher set back (790 vs. 740B.U.) than corn. Data on soluble components of cooled (85°C) starch pastes, as collected and analyzed by high‐performance size exclusion chromatography (HPSEC), suggest that amylopectin plays a significant (P<0.05) role in oat paste set back; for corn starch, amylose is the dominant factor. Solubilities and apparent molecular weights (MW) of oat starch heated (65‐120°C) under shear and subsequent sonication (0‐40s) in water or 90% methyl sulfoxide (DMSO) were also determined by HPSEC. An intermediate MW fraction was eluted on the HPSEC chromatograms only when oat starch was heated in water (100‐120°C/30min) or DMSO and sonicated, suggesting that this fraction may not be inherent in the native granule. in water, polymer solubility and peak MW increased with temperature (65‐120°C), whereas in DMSO, solubility decreased with heating (65‐100°C), while peak MW remained basically constant. Aqueous (aq) leaching at 75°C solubilized more corn amylose than amylopectin, but amylopectin and amylose co‐leached from oat starch granules. Aq leaching, at 20°C above their DSC peak ends (85 and 95°C for oat and corn, resepctively), showed more amylopectin leached from oat starch granules whereas more amylose was leached from corn starch granules.
The Effects of Extrusion Conditions on the Physical Properties of Wheat Flour Extrudates
Authors: Ryu G. H. , Walker C. E.
Published: November 2006

The effects of extrusion conditions (feed moisture content and rate, process temperature, screw speed and geometry, and die diameter) on expansion ratio, bulk density, and breaking strength of wheat flour extrudates were investigated. Extrudate samples were prepared by using a Brabender single‐screw extruder. Higher feed moisture content and process temperature were required for proper expansion. At 3.18mm die opening, the relationship between expansion and bulk density was positive. Feed rate was the most effective factor for increasing bulk density. Breaking strength was significantly decreased with increasing process temperature.

Under extrusion conditions of 22% feed moisture, 110g/min feed rate, 160°C process temperature, and 130rpm screw speed with 5:1 CR, wheat flour was puffed with low bulk density and breaking strength.
Effect of 1B/1R Translocation in Wheat on Physical and Chemical Properties of Starch
Authors: Burnett C. J. , Lorenz K. J. , Carver B. F.
Published: November 2006

Starches were isolated from near‐isoline pairs of 1B/1R translocation wheats and their parents for determination of water binding capacity, swelling power, solubility, Amylograph viscosity, scanning electron microscopy, differential scanning calorimetry and bread baking characteristics.

Translocation wheats had a statistically lower starch yield. The starches of these wheats had a lower swelling power at 60° and 80° and a reduction in Brabender viscosity after a 15 min holding period when compared with control starches. Texture scores of breads baked with starches from translocation wheats were better than those of control breads.
Nuclear Magnetic Resonance Spectroscopy of Pullulan and Isomaltose: Complete Assignment of Chemical Shifts
Authors: Arnosti Carol , Repeta Daniel J.
Published: November 2006

Over the past decade, advances in nuclear magnetic resonance spectroscopy (NMR) and increased availability of NMR spectrometers have led to the application of NMR to a wide range of problems in many fields, including environmental chemistry. Complete assignment of carbon and proton resonances is a prerequisite for using NMR spectroscopy to monitor changes in chemical structures during the course of biochemical and biological experiments. Several corrections and additions to previously published 13C chemical shifts of pullulan and isomaltose are reported here. In addition, the 1H assignments of isomaltose are presented.
Complexes of Starch with Dioic Acids
Authors: Tomasik P. , Wang Y.‐J. , Jane Jay‐Lin
Published: November 2006

Attempts are presented for the preparation of complexes of starch with a series of dioic acids (oxalic, malonic, succinic, glutaric and adipic). The complexes are isolated and characterized by potentiometric titration, powder X‐ray diffraction, characteristics of gelation and differential scanning calorimetry. These complexes contain dioic acids on the level of 1−3g per 1g of starch. Oxalic acid forms a surface complex with crosslinking involving both its carboxylic groups. Malonic acid forms surface complex with involvement of only one of its carboxylic groups and all three succinic, glutaric and adipic acids form inclusion complexes.
Gamma Radiation‐Induced Graft Copolymerization of Acrylonitrile Onto Sodium Salt of Partially Carboxymethylated Amylose
Authors: Patel Bipin K. , Sinha Vijay K. , Patel Chandrakant P. , Misra Bhupendra Nath , Trivedi Harikrishna C.
Published: November 2006

The graft copolymerization of acrylonitrile onto Sodium salt of Partially Carboxymethylated Amylose (Na‐PCMA, DA=0.313) in aqueous and in water: methanol mixed solvents system has been studied using gamma rays from Co60source as a means of initiation by the mutual method. The optimum condition for affording maximum percentage of grafting of acrylonitrile onto Na‐PCMA has been obtained by varying different reaction parameters such as total dose, monomer concentration, amount of water and composition of solvents system. The mechanism of grafting has been postulated. The resulting graft copolymer has been characterized by chemical, spectroscopic, thermogravimetric and scanning electron microscopic methods.
Concentrated Water Solution of Salts as Solvents for Reactions of Carbohydrates. Part 1: Reactions of Glucose Promoted by Concentrated Solutions of Alkaline and Alkaline Earth Metal Salts
Authors: Tyrlik Stanislaw K. , Szerszen Dorota , Kurzak Barbara , Bal Karol
Published: November 2006

Saturated water solutions of selected alkaline and alkaline earth metal salts have been studied whether or not they catalyze the formation of levulinic acid from glucose. The most active was a solution of magnesium chloride. Activity was further increased in the system (MgCl2+H+).

We observed complete inhibition of this reaction by NO3−. Contrary to the generally accepted opinion that formation of hydroxymethylfurfural is only H+ catalyzed, we observed activity of the system formed from MgO and MgCl2 when one starts from glucose. (MgCl2+ MgO) in water is alkaline.
Amylose is not Strictly Linear
Authors: Curá José Alfredo , Jansson Per‐Erik , Krisman Clara R.
Published: November 2006

Amyloses from selected corn starches were used to measure the glucoses involved in the branching points. The number of glucose α 1,6 glycosidically linked were determined by two different methods: 1) The enzymatic one measures directly quantiatively and specifically the glucoses α, 1,6 linked. 2) The other, a chemical one that measures the different n‐methylated glucoses involved in the terminal, α 1,4 linked and α1,6 linked positions.

The results obtained through both methodologies clearly indicate a good correlation. Amylose is not linear. It has very small proportion of branches and they are α1,6 glycosidically linked.
Electrochemical Synthesis of Polysaccharide‐Protein Complexes. Part 1: Preliminary Studies on Apple Pectin‐Albumin Complexes
Authors: Dejewska A. , Mazurkiewicz J. , Tomasik P. , Zaleska H.
Published: November 2006

Solid complexes of apple pectin with egg albumin could be prepared from their aqueous solutions in the 12V gradient of potential on the stainless steel electrodes. The complexes were separated as a gel on anode. The composition of the complexes was dependent on the component ratio in solution and practically independent of pH of solution which varied from 4 to 11.6 within 90 min process.
Effect of the Heat‐Moisture Treatment on the Enzymatic Susceptibility of Corn Starch Granules
Authors: Franco Célia M. L. , Ciacco César F. , Tavares Débora Q.
Published: November 2006

Normal and waxy corn starches were isolated, adjusted to different levels of moisture and heated at 100°C for 16h. The heat treated starches were hydrolysed with α‐amylase and amyloglucosidase. The starch samples were studied by determining their water‐binding capacity, pasting properties, X‐ray diffraction and by optical and scanning electron microscopy. The results showed that the heat‐moisture treatment produced an increase in the degree of crystallinity of normal and waxy corn starches at the level of 18% moisture. This result, in conjunction with a significant decrease in the enzymatic susceptibility, suggested a rearrangement of the starch molecules with strengthening of the linkages within the granules. On the other hand, the heat‐moisture treatment caused a rupture with further rearrangment of linkages within the granules for normal and waxy corn starches adjusted to the 27% moisture level. This produced a certain degree of starch degradation increasing the accessible regions of the granule to amylolysis.
Polymorphic Transitions of Amylose‐Ethanol Crystalline Complexes Induced by Moisture Exchanges
Authors: Le Bail P. , Bizot H. , Pontoire B. , Buléon A.
Published: November 2006

Vh‐type crystals were prepared by precipitation in pure alcohol of amylose solutions in dimethyl sulfoxide (DMSO). The respective influences of amylose chain length and final equilibrium relative humidity (E.R.H.) on the nature of transitions induced by moisture exchanges were studied extensively using X‐ray diffraction. The nature and kinetics of observed transitions depend on amylose chain length. If the Va form is always observed upon dehydration, A, B or mixtures of A and B forms are obtained according to the amylose chain length when rehydrating over higher water activities. Other specific transitions occurred when the Vh material was preliminary crystallized in mixture of ethanol and water (80/20,v/v). Some results suggest that these transitions occur through a transient disappearance of crystallinity and subsequent reorganization. Such mechanisms would be more conceivable than a solid state conversion from a single helical conformation (Vh type) to a double one (A and B types).
Starch Damage Part 1: Characterisation of Granule Damage in Ball‐milled Potato Starch Study by SEM
Authors: Baldwin Paul M. , Adler Jeremy , Davies Martyn C. , Melia Colin D.
Published: November 2006

Scanning electron microscopy (SEM) has been used to classify and quantify the types of damage evident in a population potato starch granules following ball milling. Whilst the majority of granules remained undamaged, a significant (p<0.01) increase in the number of granules with localized damage was observed (1.6% to 15.1%). A variety fo types of localised damage were discernable, ranging from areas where small amounts of granule surface material had been removed, to large areas possessing coarse surfaces caused by extensive removal of material. The generation of this latter category termed ‘rough faces’, was the most significant and predominant change following ball milling (p <0.05). Ball‐milling was therefore attributed to the penetration of an outer granule layer, via the removal of surface material at existing points of weakness. This produced rough, disrupted areas of the granule surface, which are more likely to be susceptible to hydration and enzyme attack.
Starch Damage Part 2: Types of Damage in Ball‐milled Potato Starch, upon Hydration Observed by Confocal Microscopy
Authors: Adler Jeremy , Baldwin Paul M. , Melia Colin D.
Published: November 2006

Confocal fluorescent microscopy was used to classify the types of damage in native and ball milled potato starch granules on the basis of their response on hydration. Damage to individual granules at room temperature was assessed using the integrity of the maltese cross and with two fluorophores, congo red and acridine orange. A variety of types of damage were found, ranging from granules that appeared physically intact with localised congo red fluorescence and a corresponding deficit in the maltese cross, to granules that had ‘exploded’, as hydration of the core ruptured the granule, leaving the outer layers of the granule split but ostensibly intact. Also found were granules with obvious fractures and apparently intact granules with fluorescent areas which sometimes exuded a puff of fluorescing material. When hydrated at room temperature the interior of granules sometimes forms a gelatinous mass while the exterior of the granules remained virtually unaffected. The differentiation of the outer layers of the potato starch granule from the inner layers suggests a macroscopic model of granule structure comprising an outer layer, that is resistant to both damage and gelation, covering a less resistant interior.
Structural and Physicochemical Changes of Potato Starch Along Periodate Oxidation
Authors: Veelaert S. , Polling M. , De Wit D.
Published: November 2006

Dialdehyde starches were prepared by oxidation with periodate. The influence of the degree of oxidation of the dialdehyde starch on its microstructural and physicochemical properties such as crystallinity, granular structure, complexing capacity with iodine and lysolecithine and water absorption are discussed. Oxidation appears to cause a gradual decrease of any microstructure, meanwhile water absorption is observed to be maximal at intermediate degrees of oxidation. A structure‐swelling relationship has been developed and compared with the washing efficiency during purification.
Determinatin of the Degree of Cationicity in Cationic Starches by Solid‐State 13C NMR Spectroscopy
Authors: Killinger William E. , Murray Daniel , Hatfield Galen R. , Hassler Thord
Published: November 2006

13C solid‐state NMR is presented as a rapid and accurate method for determining the degree of substitution in cationic starches. Data are presented for four cationic starches where the cationizing agent is a trimethyl‐substituted quarternary amine. Using a rigorous quantitative approach, NMR determined DS values can be obtained that fall within ±0.01 DS units of those obtained by traditional wet chemical methods. By employing average relaxation parameters, the analysis time can be reduced to roughly one hour at the expense of an increase in uncertainty to only ±0.03 DS units.
Gelatinization of Starch in Aqueous Alkaline Solutions
Authors: Ragheb A. A. , Abdel‐Thalouth I. , Tawfik S.
Published: November 2006

The effect of kind and concentration of alkali on the gelatinization of maize, rice and wheat starches were thoroughly investigated. No gelatinization could be observed on using the carbonate and/or bicarbonate of sodium and potassium even on using their saturated solutions, while both sodium and potassium hydroxides undergo gelatinization. Gelatinization of starch occurs immediately at a concentration of sodium hydroxide of 1.2%, while clear gelatinized pastes could be obtained at 4% or more. Infra‐red spectra of maize and rice starches before and after alkali treatment reveal that treatment of starch with sodium hydroxide is accompanied by some physicochemical changes in the structure of starch. The rheological properties as well as the apparent viscosity of the gelatinized starch pastes depend on the kind of starch as well as the nature and concentration of alkali used.
Formation of Maize Starch Gels Selectively Regulated by the Addition of Hydrocolloids
Authors: Eidam Dirk , Kulicke Werner‐Michael , Kuhn Klaus , Stute Rolf
Published: November 2006

Native maize starches containing amylose are used for manufacturing gels in food technology at concentrations of about 7%. Depending on the pasting conditions chosen, several hours may be required for the final consistency to be attained. For this reason the influence of hydrocolloids was investigated with economic factors dictating an effective concentration of approximately 5% in terms of the pure starch. The gelation process was monitored quantitatively by means of rheomechanical oscillation measurements in the linear viscoelastic range. The substances investigated were polysaccharides with chemically similar structures and classified as safe under foodstuff regulations: guar gum, locust bean gum, x‐carrageenan, t‐carrageenan, xanthan and carboxymethylcellulose (CMC). The gelation process can be significantly accelerated by a range of hydrocolloids, with the effect decreasing as follows: CMC > locust bean gum > guar gum > x‐carrageenan > xanthan. The mixtures achieved between 45% and 80% of the final gelation stability of pure starch of 100Pa. The gelation process is clearly retarded by the hydrocolloid t‐carrageenan. With the aid of the rheological data it is possible to correlate the influence of the hydrocolloids on the process of self‐aggregation and also on the resulting viscoelastic properties of the mixed gels with one another. In terms of a molecular interpretation it is possible to distinguish between exclusion effects and specific interactions in the functioning of the hydrocolloids.
Modifications in the Phenolphthalein Method for Spectrophotometric Estimation of Beta Cyclodextrin
Authors: Goel Anuj , Nene Sanjay N.
Published: November 2006

The phenolphthalein solution used in the assay of β‐Cyclodextrin is not stable and undergoes spontaneous decolorization. There is linear decrease in absorbance of phenolphthalein with time. This causes a continuous increase in error with time which is as high as 80% after one hour. A simple procedure is described in the paper to circumvent this problem allowing reproducible and reliable results to be obtained. A single reagent assay was developed by incorporating phenolphthalein in Na2CO3 solution. This resulted in stable absorbance readings and increased the linearity of assay up to 200μg/ml of β‐cyclodextrin.
The Influence of Acid Hydrolysis of Potato Starch on the Stress‐Strain Propoerties of Thermoplastic Starch
Authors: van Soest J. J. G. , Benes K. , De Wit D.
Published: November 2006

Potato starch has been hydrolysed lowering the molecular mass. The influence of starch molecules mass on the mechanical properties of thermoplastic starch has been investigated. Acid hydrolysis was performed with hydrochloric acid in various concentrations and time spans. Acid hydrolysis of the granular potato starch decreased both the molecular mass of amylose and amylopectin. The thermoplastic materials have been made by extrusion processing of the various starches with fixed amounts of water and glycerol.

The stress‐strain properties showed to be influenced by molecular mass. The materials were rubbery at 20°C and 60% relative humidity. Although the tensile stress did not change significantly, the elastic modulus increased with an decrease in molecular mass. This increase was explained by differences in starch structure and morphology. The higher of the low molecular mass materials could result in a more rapid starch structural ordering. The elongation and tearing energy increased with incrasing molecular mass. Theses effects were explained by the higher amylose chain length and amylopectin endgroups chain length resulting in a more entangled polymer matrix.
Gelatinization of Thermally Treated Starch Mixed with Sodium Hydroxide in the Solid State
Authors: Ragheb A. A. , Abd El‐Thalouth I. , Tawfik S.
Published: November 2006

The effect of thermal treatment on maize starch mixed with different amounts of sodium hydroxide, in the solid state, on its gelatinization was thoroughly investigated. Besides, the rheological properties of the products which undergo gelatinization by addition of water at room temperature after treatment were also investigated. It was found that gelatinization of thermally treated starch with sodium hydroxide in the solid state starts only at a ratio of alkali: starch of 1:10 or more regardless of the temperature of treatment.

The rheological properties as well as the apparent viscosity at various rates of shear were found to be dependent on both the temperature of treatment an the sodium hydroxide: starch ratio. Storing of the thermally treated gelatinized starch pastes for 7 days is accompanied by a remarkable increase in their apparent viscosity at any specific rate of shear which may be due to the effect of sodium hydroxide on starch during storing.
Determination of Amylose in Cereal and Non‐Cereal Starches by a Colorimetric Assay: Collaborative Study
Authors: Martinez Cristina , Prodolliet Jacques
Published: November 2006

An improved colorimetric method, based on the well‐known reaction between amylose and iodine, is described. Native starch is dissolved in ureadimethylsulfoxide and the resulting solution defatted with ethanol. An aliquot of the lipid‐free solution is then reacted with iodine and the absorbance of the blue‐coloured amylose‐iodine complex measured, thus determining the iodine‐binding capacity of starch (Blue Value). A collaborative study was conducted, according to official guidelines, to determine the method's repeatability and reproducibility: 8 participants were each sent 8 starch samples from different botanic origin for duplicate analysis. Statistical evaluation of the results gave good precision results, with an average repeatability relative standard deviation of 2.1% and an average reproducibility relative standard deviation of 5.6%. The method is, therefore, suitable to determine precisely the amylose content of native starch.
Determination of Amylose in Flour by a Colorimetric Assay: Collaborative Study
Authors: Martinez Cristina
Published: November 2006

An improved colorimetric method, based on the well‐known reaction between amylose and iodine, is described. During a first step, flour is dissolved in dimethylsulfoxide and the starch precipitated with ethanol. The extracted starch is redissolved in urea‐dimethylsulfoxide and the resulting solution defatted with ethanol. An aliquot of the lipid‐free solution is then reacted with iodine and the absorbance of the blue‐coloured amylose‐iodine complex measured, thus determining the iodine‐binding capacity of starch (Blue Value). A collaborative study was conducted, according to official guidelines, to determine the method's repeatability and reproducibility: 9 participants were each sent 7 flour samples from different botanic origin for duplicate analysis. Statistical evaluation of the results showed satisfactory precision, with an average repeatability relative standard deviation of 2.6% and an average reproducibility relative standard deviation of 9.1%. The proposed method can, therefore, be considered as reliable and can be used for routine analysis.
Effect of Talc on Properties of Corn Starch Extrudates
Authors: Bhatnagar Sandeep , Hanna Milford A.
Published: November 2006

Commercially available 0, 25, 50 and 70% amylose corn starches were extruded with up to 5% talc {(OH)2Mg3(Si2O5)2} in a single screw Brabender laboratory extruder at 18% moisture content, 140°C barrel temperature, and 140rpm screw speed. Expansion ratio, unit density, percentages of closed and open pores, porosity and molecular degradation of extruded starches were measured.

Addition of talc resulted in decreases in expansion ratio, unit density and percentage of open pores, and in increases in percentage of closed pores and porosity of extrudates. The extrudates became smaller with a greater number of round and uniformly sized cells with added talc. Gel permeation chromatographic fractionation of extrudates showed extensive degradation of fraction I with increasing talc concentrations. The talc appeared to have provided nucleation sites for water vaporization as the material exited the die of the extruder.
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

An 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

Starch 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

Es 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

Bread 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

The 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

An 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

A 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

The 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

Viscosity 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

Native 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

Annealing 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

Starch 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

A 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

Enzymic 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

Amylose 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

Two 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.