30 No. 4
Critically Evaluated Techniques for Size Separation Characterization of Starch
A better understanding of structure-property relations for starch is needed to address human and animal nutritional needs and industrial applications such as paper manufacture. Characterizing the structure is complex because one of the two types of starch in grains, amylopectin, is hyperbranched and of very high molecular weight.
Size separation techniques (size-exclusion chromatography, field-flow fractionation), with multiple detection, in principle provide powerful tools for obtaining data that are sensitive to this complex structure. However, reliable application of these methods is bedeviled by two problems: (1) not all the starch may be dissolved, and (2) shear scission may occur during separation. Recognizing these problems, several leading researchers in the field over the last few years have independently devised various protocols, typically involving the use of solvents (eluents) such as dimethyl sulfoxide of varying degrees of dryness, with or without other additives such as dimethylacetamide and LiBr, various dissolution regimens, and various flow techniques. However, there has been no comparison of the data obtained from different set-ups.
This project will bring together these leading groups to discuss the full technical details of their different procedures, including the reasons for these being chosen by the particular group, and perceived problems with these various methods. The main objective of this project is to produce a reliable means of characterizing starch by size separation techniques (such as size exclusion chromatography and field-flow fractionation), by critically examining and reconciling the various, and presently rather diverse, existing methodologies. A round-robin will then be organized to characterize the same sample by the varying techniques. The results will be used to develop improved techniques that can be used by researchers world-wide to obtain reliable and reproducible results.
For more information and comments, contact Task Group Chair Robert G. Gilbert <[email protected]>.
last modified 12 September 2008.
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