EFFECTS OF OAT GRAIN HYDROTHERMAL TREATMENTS ON WHEAT-OAT FLOUR DOUGHPROPERTIES AND BREADBAKING QUALITY

Hydrothermal treatments, which are routine in oat processing, have pro found effects on oat flour dough rheological properties. The influence of roasting and steam treatments of oat grain on dough mixing and bre adbaking properties was investigated when hydrothermally treated oat f lour was blended with wheat flour. Roasting of oat grain (105 degrees C, 2 hr) resulted in oat flours that were highly detrimental to wheat flour dough mixing properties and breadbaking quality. Steaming (105 d egrees C, 20 min) or a combination of roasting and steaming of oat gra in significantly improved the breadbaking potential of the oat flours. The addition of oat flours increased water absorption and mixing requ irements of the wheat flour dough and also decreased bread loaf volume . However, at the 10% substitution level, steamed oat flours exhibited only a gluten dilution effect on bread loaf volume when wheat starch was used as a reference. Oat flour in the breadbaking system decreased the retrogradation rate of bread crumb starch. The results indicate t hat adequate hydrothermal treatments of oat grain are necessary for oa t flour breadbaking applications. Steamed oat flours used at a 10% lev el retarded bread staling without adversely affecting the loaf volume.