391 Effects of genotype and growing location on the dough mixing characteristics, protein content and protein quality of extra strong Glenlea-type wheats.

C. LUKIE and H. D. Sapirstein. Department of Food Science, University of Manitoba, Winnipeg, MB R3T 2N2.

Canada Western Extra Strong (CWES) wheats have a relatively high content of insoluble glutenin (IG) protein which appears to be related to the distinctly long mixing times of CWES doughs and their high tolerance to overmixing. This study examined the effects of genotype and location on these properties, as well as flour protein (FP) content and protein quality measured by the amount of 50% propanol IG. Six cultivars, including four CWES and two CW Red Spring (CWRS) wheats, were grown in six locations in western Canada. A computerized 2 g Mixograph was used to evaluate fixed absorption dough mixing characteristics of flours subjected to various treatments including blending with prime starch to bring all flours to a common (10%) protein content (CPC). Mixogram and other parameters varied in their susceptibility to location effects as follows: mixing time (MT) to peak dough resistance (PDR) > work input (WI), FP > PDR > IG. With the exception of FP and PDR, genotypic effects were greater than location effects. Mixing doughs at a CPC improved discrimination of dough strength between CWRS and CWES cultivars, but not within the CWES wheats which could be clearly separated into two levels of strength. Expressing IG content of flour as a percent of FP, provided very good prediction of MT (R(^2) = 0.64) and WI (R(^2) = 0.83) across all cultivars and locations.