288 Gluten “gelatinization”: II. Gluten composition, gluten thermostability and flour quality.

M. I. P. KOVACS (1), P. Chen (2), A. P. Sarkar (2), J. Long (2), B. X. Fu (2), Ch. Wang (1), G. Dahlke (1), N. K. Howes (1), R. DePauw (3), R. McKenzie (1), and D. Brown (1). (1) Agriculture and Agri-Food Canada, Cereal Research Centre, 195 Dafoe Road, Winnipeg, Manitoba, R3T 2M9, Canada; (2) Canadian International Grains Institute, Winnipeg, Canada; (3) Semi-Arid Prairie Research Centre, Agriculture & Agri-Food Canada, Swift Current, SK S9H 3X2.

Here we would like to show that the increased flour quality value for noodle quality is due chiefly to the increased thermoinstability of the different gluten components. Heat “gelatinization” of gluten with and without NaCl and its viscoelasticitic properties was investigated. In this study we used a set of 20 cultivars having a wide range of glutenin subunits and flour quality. The monomeric proteins, polymeric proteins (insoluble and soluble glutenins) and the residual protein fraction of the gluten was studied in relation to flour quality. The total relative amount of monomeric proteins had more influence on flour quality than the amount of insoluble and soluble glutenins relative to each other or the residual proteins. Viscoelasticities of heat “gelatinized” gluten (determined from the creep curve) were correlated with over 3o flour quality parameters and its relationship to those parameters will be discussed. The effect of NaCl on the viscoelastic properties of gluten will also be discussed. We would like to postulate that the monomeric proteins and the proteins folded into globular shape, consequently with solvent accessible surface area relative to the total volume of the gluten (linear monomer versus globular shaped mono or polymer), are the most essential determinant of thermoinstability and gluten strength and not the type of glutenin subunits.