1. Nitrogen Management for Enhanced Protein: Consideration of Protein Quality for Breadmaking C. Rawluk 1, C. Grant 1, O. Lukow 2, A. Johnston 3 and R. McKenzie 4 1 AAFC Brandon Research Centre, 2 AAFC Cereal Research Centre, 3 PPIC, 4 Alberta Agriculture

2. Protein Content and Quality Grain protein concentration increases as N availability increases Higher protein content generally equated with higher protein quality for breadmaking Does higher protein content necessarily mean better quality?

3. Protein Content versus Quality Of particular concern at high N rates or late in-crop N applications How do components of breadmaking respond to N? How are components of breadmaking related to protein content?

4. Evaluating Protein Quality –flour and dough quality: capacity for water absorption by flour evaluation of dough during mixing and development Optimization of viscoelastic properties for dough expansion and retention –bread loaf quality: baking evaluation - size of loaf High gas production and elasticity for gas retention to produce large loaf

5. Protein Quality and Gluten Gluten proteins largely determine protein quality –Glutenins - elastic component of dough polymeric HMW and LMW proteins –Gliadins - viscous component of dough monomeric single-chained polypeptides Relative proportion of glutenin and gliadin and glutenin structure and distribution (HMW-GS/LMW-GS)

6. Effect of N Rate: Flour Protein and FAB Melfort 1998 AC Barrie r = 0.88 P < 0.0001

7. Effect of N Rate: Flour Protein, FST and FDDT Brandon 1999 r = 0.64 0.0069 r = 0.84 P < 0.0001 Katepwa

8. Effect of N Rate - Bread Baking

9. Protein Content and Quality: Cultivar Difference +0.6 -0.3 +0.9 +0.7 +0.4 +0.7

10. Effect of N Source and Timing: Flour Protein and FAB

11. Effect of N Source and Timing: Flour Protein and FDDT

12. Effect of N Source and Timing: Flour Protein and FST

13. Effect of N Source and Timing: Flour Protein and FTBD

14. Effect of N Source or Timing

15. N Rate, Timing and Source What benefits protein content tends to also benefit protein quality protein content, flour water absorption, dough strength and stability, and loaf volume increased with increasing N rate combination of timing and source more important than source alone possible exception at very high N rates where may have other limiting factors eg. N:S ratio in grain