Anton Huber

Karl-Franzens-Universität Graz | KFU Graz · Department of Physical and Theoretical Chemistry

This review focuses on cationic starches with a low degree of substitution (<0.06) which are mainly used for production of paper-based products. After a brief introduction on starch in general, cationization pathways and importance of cationic starches in paper production, this review emphasizes on the analytical challenges from different perspecti...

The polyanionic heteropolysaccharide xanthan in aqueous environment and various co-dissolved cations comprises a homogeneous partition of dissolved supermolecular and nanostructured objects more or less stabilized by electrostatic interactions. The capability of "xanthan/water/modifier (XWM)"-systems to tune viscosity primarily is correlated with p...

The polyanionic heteropolysaccharide xanthan in aqueous environment and various co-dissolved cations comprises a homogeneous partition of dissolved molecules and a heterogeneous partition of supermolecular and nano-structured objects more or less stabilized by electrostatic interactions. The capability of 'xanthan/water/modifier (XWM)'-systems to t...

The influence of alkali concentration, temperature, concentration of urea and KSCN on the shapes and sizes of wx corn starch precipitates (isolated via nanoprecipitation) were studied. A strong correlation was found between the molecular and hydrodynamic characteristics, determined by using asymmetrical flow-field flow fractionation (AF4), and the...

Starch dispersions/solutions were prepared by heating native pea starch in 1 M NaOH(aq) at various temperatures (50–100°C) using a dedicated microwave reactor. The influence of temperature upon the apparent molecular and hydrodynamic characteristics was investigated employing asymmetrical flow field flow-fractionation coupled with multi-angle light...

Pre-gelatinized wx corn starch dispersions in aqueous media were heated at various temperatures ranging from 100 to 200°C (in 20°C increment) employing a dedicated microwave reactor. The influence of varying temperature upon the apparent molar masses and sizes of pre-gelatinized wx corn heated in aqueous media (water and 1 M KSCN) were determined u...

The nano-precipitation of native starches is a straight-forward method for isolating starch nanoparticles. The morphology and sizes of the precipitates were highly influenced by the botanical source of starch, volume of ethanol used for precipitation, and the nature of drying surfaces. The apparent molar masses and sizes of various starches followi...

Fructo-oligosaccharides (FOSs) of a six year old agave plant variety, Agave tequilana, were isolated and fractionated by 2D preparative chromatography (SEC and rpHPLC). Structural analyses of different FOS-fractions were performed by reductive methylation analysis connected to GC/FID identification and NMR-analysis. FOSs from leaves (d.p. 3-8) cont...

1 Introduction Fructans are classified in three subgroups depending on their glycosidic linkage and branching, whereby the fructose is always in its b-furanosidic form (Meier and Reid, 1982; Vijn and Smeekens, 1999). Inulin is a non-branched fructan occurring in Asterales consisting of b(2→1) linked fructofu-ranoses with a terminal glucose in sucro...

The application of statistic thermodynamic principles to the biosynthesis of inulin explains the synthesizing and degrading activities of the fructan:fructan fructosyl transferase (FFT) enzyme as well as the molar mass distribution of native inulins. The direction of the FFT enzyme action is energetically forced by maximization of the mixing entrop...

Hydrodynamic properties of aqueous wx corn starch (native, un-pregelatinised) dispersions treated in a dedicated single-mode microwave reactor at temperatures ranging from 180 to 210 degrees C were determined using asymmetrical flow field-flow fractionation coupled with an RI detector. The dedicated microwave reactor enabled the fine control and mo...

Erwinia amylovora, causing fire blight of apple, pear and some ornamentals, Erwinia pyrifoliae, causing Asian pear blight, and Pantoea stewartii, causing Stewart's wilt of sweet maize, synthesize capsular extracellular polysaccharides (EPSs) with a high molecular mass. The EPSs are virulence factors and form viscous aggregates, which participate in...

The apparent average molar masses (Mw,app), apparent average radii of gyration (Rg,app), of native sago starch and fractions were determined using asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and refractive index detectors (AF4/MALS/RI). Amylose-type (Fraction A) and amylopectin-type (Fraction B) were chemica...

The apparent average molar masses (Mw,app) and apparent average radii of gyration (Rg,app) of native tapioca starch and fractions were determined using asymmetrical flow field flow fractionation (AF4) coupled with multi-angle light scattering and RI detectors (AF4/MALS/RI). AM-type (Fraction A) and AP-type (Fraction B) were chemically separated fro...

The apparent average molar masses (Mw,app), apparent average radii of gyration (Rg,app), diffusion co-efficients (DT), and hydrodynamic radii (Rh) of normal corn (maize) starch and fractions were determined using asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and refractive index detectors (AF4/MALS/RI). AM-typ...

Modification of the most probable distribution functions by onsidering the molar mass of the end group and the reactive moiety for Flory’s statistical distribution models for accurate prediction of degree of polymerization distributions of short chain carbohydrate polymers such as alkyl polyglucosides. Additional introduction of the Gamma function...

Starch is a highly disperse material with broad distributions of molecular sizes and geometries. Its dissolution in aqueous media is difficult to achieve and it tends to form aggregates through both inter- and intra-molecular interactions. Asymmetrical flow field-flow fractionation (AF4) is a suitable technique for the separation of such macromol...

A detailed study of the elution behaviour, apparent molecular characteristics and hydrodynamic properties of amylopectin-type fraction (isolated from normal corn starch) in aqueous media employing asymmetrical flow field-flow fractionation (AF4) was undertaken by systematically varying the channel flow (F(ch)), cross flow (F(cr)) and F(cr)/F(ch) ra...

The apparent average molar masses (Mw,app), apparent average radii of gyration (Rg,app), of native sago starch and fractions were determined using asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and refractive index detectors (AF4/MALS/RI). Amylose-type (Fraction A) and amylopectin-type (Fraction B) were chemica...

This book details polysaccharides and other important biomacromolecules covering their source, production, structures, properties, and current and potential application in the fields of biotechnology and medicine. It includes a systematic discussion on the general strategies of isolation, separation and characterization of polysaccharides and prote...

Characterisation of the distribution functions describing size-related parameters of individual whole starch molecules in solution is important for establishing biosynthesis–processing–structure–property relations, for improvements in human and animal nutrition, and for industrial applications of starch. Current techniques for obtaining these distr...

There is no doubt that 'Renewables' will be the dominant raw materials in the future. Adequate processing of these materials combined with the increasing request for sustainable technologies, however, cannot be achieved by simple substitution of fossil by renewable raw materials. Some of the extra-challenges to be handled when dealing with renewabl...

For an appropriate and reliable classification of fructan plants from taxonomic and genetic point of view and for adequate utilization in food, feed, non-food products and pharmaceuticals knowledge of composition, structural details, degree of polymerization distribution (mean values of degree of polymerization) and the magnitude of fructans in sto...

Comprehensive analysis of polysaccharides basically includes determination of carbohydrate composition (in case of homo-polysaccharides only determination of kind and extent of branching), determination of glycosidic linkages with corresponding structural details and determination of degree of polymerization distribution. A range of chromatographic...

Polysaccharides are introduced as the major renewable resource with high performance in terms of functionalities within organisms at any level of organization in natural environment. Construction principles and nomenclature of polysaccharides are explained. Particular focus is given to the fact that polysaccharides integrate water in morphology and...

A major capability of polysaccharides in aqueous media is their tendency for aggregation and dynamic formation of supermolecular structures. Even extended dissolution processes will not eliminate these structures which dominate many analytical approaches, in particular absolute molecular weight determinations referring to light scattering data. An...

In order to introduce and use renewable resources in several applications, there is a constant need to analyze and study the renewable raw materials. In this chapter, attention is paid to the technical aspects of how these compounds can be analyzed. Of course, this is a very broad area and there are thousands of methods available to study all the d...

The concept of the use of renewable resources is implicitly connected to the idea of integral valorization, meaning that it is important to be able to use the product delivered by nature or by agriculture completely. Of course, this concept also holds for other types of production and needs to be one of the major concepts in designing new applicat...

Starch is the most important form of energy reserve of crops and is formed annually worldwide in huge amounts which constitutes a significant commercial importance. The most important application of starch was and is for food and animal feedstock. Whereas the main source of starch in Europe are potatoes in the US most starch comes from maize. In t...

Fructans are worldwide important components in human nutrition with slight differences due to geographic and cultural peculiarities. Sprouts of chicory, tubers of Jerusalem artichoke, globes of artichoke, onion, leek, garlic and sprouts of asparagus are utilized as vegetables in different ways of preparation. Onion, garlic and chives are used as sp...

Microdialysis was used for sampling enzyme hydrolysis products of starch hydrolysed with β-amylase, pullulanase, and/or isoamylase, to obtain information about the molecular structure of starch. Starches from waxy, normal, and high amylose maize, and from normal and genetically modified potato (amylose deficient) were used, and also commercial pota...

Colonization of host plants by the fire blight pathogen requires synthesis of capsular exopolysaccharide (EPS) (1). Erwinia amylovora synthesizes the homopolymer levan via a secreted levansucrase from sucrose in the environment and an acidic polymer. Amylovoran consists of repeating units with four galactose and one glucuronic acid residues as well...

Chromatographic separation of polysaccharide components, particularly separation by means of size exclusion chromatography (SEC) according to different occupied volumina, is an appropriate analytical, semipreparative, and even preparative tool for obtaining detailed information about characteristics and contributions of individual fractions to the...

The fire blight pathogen Erwinia amylovora synthesizes an acidic extracellular polysaccharide (EPS), named amylovoran, and the related corn pathogen Erwinia stewartii produces a structurally similar EPS named stewartan. Biosynthesis of amylovoran was examined in an in vitro system using EDTA-treated cells and following incorporation of radio-labele...

Selected starches, i.e. waxy maize, amaranth, quinoa, wheat, millet and buckwheat starches, were investigated with respect to their technological properties such as gelatinization, stability to mechanical stress, resistance to conditions and stability in continuous freeze/thaw cycles. Technological properties are correlated with molecular features...

I. Abbreviations II. Introduction A. Dataprocessing B. Broad Standard SEC-Calibration C. Universal SEC-Calibration D. Molecular weight / Degree of Polymerization: Average values and Distributions III. Dextran Gels A. Preparative Sephacryl S-1000 Semi-preparative Sephacryl-sysem S-200 / S-400 / S-500 / S-1000 B. Semi-preparative Sephacryl S-1000 C....

The assignment of 13C and 1H NMR signals of three highly short-chain branched α-D-glucan samples from animal tissue (glycogen) of different provenience, dissolved in dimethylsulfoxide, was achieved using two-dimensional H-H and C-H correlated spectroscopy. The results were comparable to those recently obtained for plant derived short-chain branched...

Technological properties of raw materials from renewable resources, such as glucans from starch, are determined by molecular characteristics: molecular weight (degree of polymerization) distribution, occupied volume, branching pattern, kind and magnitude of intra- and inter¬molecular interaction. In the course of biosynthesis and metabolism there i...

Macroscopic properties of starch are determined by molecular characteristics such as molecular weight distribution, branching characteristics, glucan coil packing density and coil dimensions. For the determination of these characteristics glucan fractions of high-amylose corn starch were dissolved in DMSO to get a true particle solution without agg...

From the aqueous growth medium of Red Microalgae Porphyridium sp., anionic polysaccharide was separated by centrifugation and dialysis. Xylose, glucose, galactose, mannose, rhamnose, arabinose, methyl-pentoses, dimethyl-hexoses, glucuronic acid and sulfated sugar-units were identified as constituting monomers. By means of size-exclusion chromatogra...

The photoluminescence quantum efficiencies of poly(para-phenylenevinylene)s (PPVs) synthesized via different precursor routes are investigated. The results are discussed with respect to the different preparation conditions of the precursor polymers, which are characterized by molecular weight distributions obtained by means of chromatography multid...

The waxy pecto-cellulosic cuticle of cladodes of the columnar cactusCereus peruvianus (19% of the whole phytobiomass; dry wt) is a source of an α-d-polygalacturonic or pectic acid (35–40% yield, on a dry wt based on the wax-free pectocellulose layer). Warm EDTA/oxalate or room temperature strong acid/alkali cycles are efficient for pectic acid extr...

The enzyme levanase encoded by the sacC gene from Bacillus subtilis was overexpressed in Escherichia coli with the strong, inducible tac promoter. The enzyme was purified from crude E. coli cell lysates by salting out with ammonium sulfate and chromatography on DEAE-Sepharose CL-6B, S-Sepharose, and MonoQ-Sepharose. The purified protein had an appa...

The enzyme levanase encoded by the sacC gene from Bacillus subtilis was overexpressed in Escherichia coli with the strong, inducible tac promoter. The enzyme was purified from crude E. coli cell lysates by salting out with ammonium sulfate and chromatography on DEAE-Sepharose CL-6B, S-Sepharose, and MonoQ-Sepharose. The purified protein had an appa...

Molecular characteristics, especially the branching-structure, of glucans from starch granules isolated from tubers of potato species Ukomo are determined. Granule-fraction with different mean-diameters are provided by sedimentation as inital separation step for further investigations. Then aqueous/DMSO dissolved starch glucans were separated into...

A new methodology for the analysis of starch which combines complexation/precipitation-techniques with size exclusion chromatography and enzymatic debranching is described. Application of this methodology yields detailed information about the microstructure of starch. The non-branched/long-chain-branched glucans (amylose) of wrinkled pea and high a...

As a first step in the characterization of inulin/inulinase systems the specific mode and extent of the exo-inulinase-catalysed hydrolysis of Jerusalem artichoke inulin was studied. A non-Michaelis-Menten kinetic approach was applied for an adequate characterization of enzymatic activity. Since average molecular weight and molecular weight distribu...

The characterization of starch- polysaccharides including preparative size-exclusion chromatography (SEC), fractionation and subsequent characterization utilizing analytical SEC combined with specific (multi-) detection supported by personal computer and adequate software yields a lot fo charactersitic parameter values for the investigated sample....

For three different polysaccharides (Inulin, Sinistrin and Dextran) of about identical weight average molecular weight (Mw) and number average molecular weight (Mn) an extended characterization was performed combining results from SEC-DRI/LALLS-investigations and data from universal calibration. The results are summarized. For aqueous dissolved pol...

Size exclusion chromatography (SEC) combined with double detection, utilizing a differential refractive index (DRI)- and a low angle laser light scattering (LALLS) - detector represents a powerful experimental set-up in the field of chromatography-multidetection (C-MD). By means of these techniques high-quality information for profound polymer char...

Starch branching enzyme (Q-enzyme; EC 2.4.1.18), isolated from young, mature potato tubers (Solanum tuberosum L.) and purified by ammonium sulfate precipitations, hydrophobic-interaction chromatography, and size-exclusion chromatography, was completely free of phosphorylase (EC 2.4.1.1) and alpha-amylase (EC 3.2.1.1) activity, had a molecular mass...

The columnar cactusCereus peruvianus provides various compounds of interest that account for most of its 10% dry wt content. Included are acidic gum and cellulose as the highly polymerized carbohydrate components, and a complex waxy lipid fraction. The major gum fraction (1.5 g% of the fresh phytobiomass on single aqueous extraction) is an uronylat...

The preparation of low molecular weight amyloses with modified terminal groups in a DP range of 4-25 was carried out by enzymatic synthesis using either potato phosphorylase or phosphorylase b from rabbit muscle. p-Nitrophenyl-alpha-D-malto-oligomers with a minimum chain length of five glucosyl residues served as primers; glucose-1-phosphate was th...

The combination of classical size-exclusion chromatography (SEC) and personal computer-supported multidetection of universal and specific polymer-solution properties will yield a wide-range of parameter values for the characterization of polymers in solution. By using a concentration detector and a low-angle laser light scattering (LALLS) detector...

1-F-Fructan/1-F-Fructan-Fructosyltransferase (FFT, EC 2.4.1.100) catalyses the transfer of a single fructose residue of an inulin-type fructan as donor to an acceptor. The donor must have a degree of polymerisation (DP) of at least 3 and the acceptor a DP of at least 2. High Performance Gel Permeation Chromatography (HPGPC) combined with an on-line...

The process of enzymatic degradation of the high-molecular hydroxyethyl-cellulose was followed by means of static low angle laser light scattering (static LALLS) which proved to be an excellent analytic method to obtain continuously an information about the decrease of the weight average molecular weight Mw without any manipulation of the substrate...

The results of a study aimed at determining the nature of the cellulose/cellulase reaction system are presented. The conclusions of the report emphasize the importance of the substrate in the reaction kinetics, and the heterogeneity of the system. There are 42 references.