  2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center  |
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Biochemical studies of puroindoline proteins in relation to the endosperm texture of hexaploid wheat. L. DAY (1), P. Greenwell (2), D. G. Bhandari (2), and J. D. Schofield (1). (1) The University of Reading, School of Food Biosciences, P.O. Box 226, Whiteknights, Reading RG6 6AP, UK; (2) Campden and Chorleywood Food Research Association, Chipping Campden, Glos. GL55 6LD, UK.
Puroindolines (PINs) are a family of very basic (pI>10), amphiphilic, low molecular weight, highly surface active, non-gluten proteins of wheat. Despite being relatively minor components of wheat flour, PINs have been proposed as the main controlling element of grain softness. Structural properties of individual puroindolines purified from British hexaploid wheat varieties, two of soft endosperm textures and four hard, were characterised using capillary electrophoresis (CE) and mass spectrometry (MS). The most abundant form, PIN-a was found to be identical in all varieties regardless of their endosperm texture, while PIN-b was polymorphic, between the soft and hard classes, and amongst the hard varieties. For the first time, the molecular masses of different PIN-b mutations were determined. Different alleles of PIN-b were also detectable by their migration times in CE. A single grain CE screening method was therefore developed. Using the ratio of the peak areas, or of the migration times of PIN-a to PIN-b, not only the soft and hard varieties of hexaploid wheat could be distinguished, but also the different alleles of PIN-b within the hard varieties.
Copyright 2001
The American Association of Cereal Chemists