Team Leader: Anton Huber (University of Graz, Austria)

Abstract:
Although starch is well known and used for thousands of years the molecular basics for technological performance still needs research and discussion. In particular the role of non- and minor-branched components (amylose) and more- / heavily-branched components (amylopectin) in aqueous environment needs detailed investigation. Starch glucans in aqueous media tend to form supermolecular structures which hardly may be distinguished from constituting individual polymer molecules. These aggregates are not covalently bound but dynamically H-bond fixed and any time the result of density (concentration) of the system, present co-materials and varying kind and magnitude of applied stress to the system. Hence, typically observed structures rather are due to interaction phenomena than to individual molecule mass and geometry, however, individual more or less branched glucan polymers are the actual background of these materials.

Nevertheless, a scheme for a datasheet taking these facts into consideration will be developed and illustrated for selected starch samples. Additionally, the datasheet of native and modified starch samples will be adjusted by feedback from obtained production scale material qualities and correlated molecular level characteristics.

Objectives:
Investigation of selected native and modified starch samples in dilute regime dimension, conformation and interactive properties of constituting polymer molecules: establishing sequences of destructive and non-destructive techniques;
Investigations of selected native and modified starch samples at concentrations exceeding overlapping concentration c* / dense systems characteristics of gel-forming, colloidal supermolecular structures: establishing rheological / viscosimetric and thermoanalytical techniques;
Investigation of starch blends surface and interface properties of dense starch and starch-blend systems: molecular background, supermolecular structures, geometry, dynamics, stability and re-organization capability on applied thermal, mechanical, chemical and enzymatic stress.
Peparation of starch analogous glucans in laboratory scale
Preparation / production of non-/minor branched starch glucans (amylose) in laboratory and pilot plant scale;
Application of starch-glucan fractions for technological purposes in laboratory and pilot-plant-scale

Contribution of the project: Knowledge of natural polysaccharide super molecular assemblies. Starch is a regularly used polysaccharide as well in the food as in non-food sector. Establishing a reasonable sequence of analytical techniques and methods characterizing starch, modified starch and fractions is a basic requirement to establish propertyperformance relationships and to improve applicability and performance. Therefore, as well dimensions and dynamics of constituting molecules as dimensions and performance of supermolecular structures need to be investigated compared. This application contributes also to the Fundamental Theme 1 research project, providing a generally accepted analytical strategy and tools as well as reference materials.

Importance for EPNOE community and industrial partners:
Although starch is applied as well in the food as in non-food sector there is still discussion on reliability of determined molecular characteristics. These characteristics however, are basic data to establish property-performance relations and finally qualify starch batches for one or the other purpose. A to be suggested analytical scheme is supposed to make data easier to compare.
Additionally, the instance of starch may be kind guiding line for other kind of polysaccharides.
The advantage for industrial partners within EPNOE obviously is the supposed scheme and possibilities for discussion on particular problems.

Importance for the characterisation of the polysaccharide raw materials:
Starch is obtained from rather different sources, in particular from tubers and seeds. However even leaves and stems of plant materials contain starch and might be of interest for certain applications. Due to this widespread spectrum an even widespread spectrum of incoming raw material qualities has to be expected. Reliable characterization of these raw materials is a basic requirement for appropriate and optimized utilization.

Importance for the characterisation of polysaccharides processability:
Processing of starch materials modifies the starting material and changes macroscopic performance of starch based materials. Controlled modification requires at least a zero order relation between molecular level characteristics and technological material qualities. Well specified and reliable molecular characteristics in terms of dimensions, conformation and interactive properties are basic requirement to establish such a relation.

Applicability to the different kind of polysaccharides:
In terms of raw material qualities in native biological systems starch is rather unique and starch properties hardly may be transferred to other kinds of polysaccharides. However, starch is an illustration for tuning of material qualities in biological systems by minor variations in branching pattern and oxidation status, for instance by phosphorylation. Another feature is the fact that each starch molecule contains one unique functional group: a terminal hemiacetal which may be subject for controlled modification, as well for analytical purposes investigating colligative properties or technological applications coupling specific functionalities at the hemiacetal terminal.
Starch is rather well established in the food sector, however, mostly as bulk material: functionalized starches may be of increasing interest, in particular referring to the term nutraceuticals.
A major quality of starch is the capability to structure aqueous media even at very low concentrations. Hence, technological properties such as biocompatible immobilization or release may be a target for non-food applications.

Potentiality to transform them into marketable products:
Starch producers as well as manufacture need well standardized starch materials and, hence, evaluated and reliable analytical techniques and methods characterizing starch and starch fractions. As technological properties of starch based materials depend on molecular characteristics such a scheme needs to include as well dimensions, conformation and dynamics of constituting molecules as dimensions and performance of supermolecular structures. The round robin test is supposed to provide reasonable analytical scheme for starch and starch fractions.
Transformation into marketable products will be by publishing the results, providing well defined reference materials and offering analytical services.