S. Uthayakumaran, C.W. Wrigley, and I.L. Batey, Food Science Australia and Wheat CRC, North Ryde (Sydney), NSW 1670, Australia; W. Bushuk, Department of Food Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2; G.L. Lookhart, Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506 USA
Gliadin and Glutenin: The Unique Balance of Wheat Quality
Pages 307-331
DOI: https://doi.org/10.1094/9781891127519.014
ISBN: 978-1-891127-51-9
Abstract
The gluten proteins provide a remarkable document portraying the genotypic identity of a grain of wheat, plus valuable clues about its ancestry. This information is recorded via the genetic code and indicated in its protein composition. The reliability of this information may appear to be surprising, since the gluten proteins are “only” storage proteins, having no apparent function in the plant other than to provide a source of amino acids for the germinating seed. From this view point, why should the plant “bother” to provide exact fidelity of protein composition? The obvious answer is that the processes of transcription and translation apply equally to storage proteins as to any other protein class.
As a result of this fidelity to genotype, analysis of gluten-protein composition has become the main laboratory test for genotype identity. The complementary function of the storage proteins is to provide mankind with their unique dough-forming properties. This offers the protein analyst the further opportunity of predicting grain-quality attributes from protein composition (described in Chapters 8 and 9), in addition to the identification of genotype.
Varietal identification has traditionally involved visual examination. However, this approach is subjective, relying on the experience and expertise of the inspector. Electrophoretic methods have been available as a more definitive alternative since the 1960s in various formats. Chromatographic methods, and more recently capillary electrophoresis, have been used as further alternatives to meet the increasing requirements for variety identification.
This chapter describes the value and the means of implementing these approaches to genotype identification in their many applications in the wheat industry.
