2007 Annual Report 1a.Objectives (from AD-416) This project will further the knowledge of the relationships between gluten strength, rheological properties, and rapid predictive tests for wheat functional quality. 1b.Approach (from AD-416) Samples (15) of pure variety hard red spring wheat will be milled into flour. Gluten extraction procedures, involving variation of solvents, pH, and centrifugation will be optimized to accentuate differences among cultivars. Rheological tests will be developed that also accentuate these differnces. Near-infrared models for gluten rheologial parameters will be developed. 3.Progress Report This report documents research conducted under a Specific Cooperative Agreement between ARS and Cornell University. Additional results of the research can be found in the report for the parent project 1265-44000-007-00D "Optical Properties of Small Grains for Rapid and Objective Assessment of Quality and Safety." Work in the prior year yielded two experimental methods that allow for unambiguous separation of delayed elastic effects and plastic flow in gluten. The first method is a "rapid" shear creep-recovery test, while the second method is a large deformation tensile test. Gluten in dough is subject to a wide range of shear and extensional stresses and strains in practical uses. For example, mixing, sheeting, oven rise, hand-pulled noodles, etc. These two tests are designed to provide objective measures of both the linear (small stress) and non-linear (large deformation) viscoelasticity of gluten. In the past year, creep-recovery and tensile testing of washed doughs was completed for 18 wheat cultivars, flours of which were provided to Cornell University by USDA, Grain Inspection, Packers and Stockyards Administration (GIPSA). An important finding was that equilibrium or "near-equilibium" values of the recoverable extensibility of gluten were obtained for creep times much shorter than those needed to achieve steady-state flow if the recovery time was substantially longer than the preceding creep time. All glutens showed substantial delayed elastic effects for the test conditions used here. Delayed elasticity is essentially a relaxation process, i.e., structural units "relax" into the equilibrium condition for the applied stress probably via a bond-breaking and re-forming process. The range of recoverable extensibility for the breadmaking cultivars was quite wide, varying by almost 400 percent, which suggests that the usual protein subunits responsible for breadmaking performance can not soley explain differences in the viscoelastic properties of whole wet glutens. Further work is aimed at reconciling results of creep-recovery, dough and gluten extensibility, biochemical wheat quality and bread quality. Monitoring of this project occurs with conference calls, site visits and electronic correspondence.