Effect of Extraction Methods and Wheat Cultivars on Gluten Functionality

ABSTRACT

The functionality of gluten extracted from Canada Western Red Spring (CWRS) and Canada Western Extra Strong (CWES) wheat flours was evaluated and compared. The extra-strong wheat cultivars had stronger dough properties and produced smaller bread loaves than AC Barrie. Modifications of a starch displacement gluten extraction method were evaluated. For optimal gluten formation and extraction, water to flour ratio of 0.87% and dough mixing to 30% after peak dough development were used. Water and cold ethanol were compared for their effectiveness in gluten extraction by evaluating gluten yield and functionality in a soft wheat flour blend. The ethanol method produced higher yields of gluten, but these gluten extracts had significantly lower protein contents than the respective glutens extracted with water. Farinograph analyses of soft wheat flour fortified with gluten extracts to 14.5% protein content showed significant differences in dough development time, stability and mixing tolerance index between water- and ethanol-extracted gluten extracts; glutens extracted with ethanol had significantly stronger dough properties and also had higher 50PI:50PS gluten ratios. Whereas ethanol-extracted gluten decreased or had no effect on loaf volume, water-extracted gluten improved bread loaf volumes when added to soft wheat flour. The inherent differences in quality between CWRS and CWES flour was reflected in the gluten extracted by water, but not in the gluten extracted by ethanol.