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Current Project

Polymer Division (IV)
Chemistry and the Environment Division (VI)
and Chemistry and Human Health Division (VII)


Number: 2004-022-3-400

Title: Terminology and measurement techniques of starch components

Task Group
Melissa Fitzgerald

Members: RG Gilbert, Matthew Morell, Harald Pasch, Louise Slade, Takayuki Umemoto, Richard Visser, and Jurgen van Moller

The aims of this project are (1) to reach agreed definitions of the three types of starches, and (2) to explore reliable and reproducible means of measuring the relative amounts of each in a given sample. At present, different laboratories report different results for what ostensibly is the same quantity.

There are two well known types of starch in cereals, amylose, or apparent amylose, and amylopectin; research indicates a third. All are polymers of glucose. Amylose, or apparent amylose, is amorphous and contributes to most, if not all, the cooking and processing properties of cereals and tubers. Amylopectin is semi-crystalline and branched and accounts for the greatest proportion of starch in cereals and tubers. The third type is amorphous and branched and its functionality is still unknown.

IUPAC has invested resources into the nomenclature of starches, but there is still no agreed description of amylose, and there is no agreed method to measure it. Thus measured values for amylose content are inconsistent between laboratories. Recent research has made significant progress in understanding the structure of the starches. This proposal is designed to bring together people from around the world who research starch structure, people who need to understand the functionality of the starches, people, including from industry, who need to measure the ratio of the different starches, and people with knowledge of terminology.

The measurement techniques will be the iodine method commonly accepted to give the relative amounts of amylose and amylopectin, and both capillary electrophoresis and multi-detector size-exclusion chromatography (with analysis by MALLS, DRI, MALDI and NMR of the eluent) to provide molecular weight distribution for both a given starch and the same starch which has been fully debranched by debranching enzymes. These data, for a wide variety of starches, either currently available, or which will be measured for this purpose in the laboratories of the Task Group members, will form the basis for agreed definitions of starch types in terms of these quantitative distributions.

Two meetings are planned. The first will be a preliminary meeting to define a 12 month action plan for describing and measuring the starches, and will run in conjunction with an IUPAC symposium on biopolymers in Mauritius in June 2005. The issues and actions will be managed by electronic communication for the next 12 months, and then a second meeting will be held at the International Rice Research Institute in the Philippines to wrap up and to finalise the recommendations.



Last update: 30 May 2005

<project announcement to be published in Chem. Int.>


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