FACTORS IN HARD WHEAT-FLOUR RESPONSIBLE FOR REDUCED COOKIE SPREAD

Time-lapse photography showed that, during baking, the diameter of sug ar-snap cookies increased linearly then suddenly became fixed. Therefo re, cookie diameter was a function of spread rate and set time. Cookie s made with soft wheat flour were significantly larger in diameter (18 4 mm) than those made with hard wheat flour (161 mm). Cookies made wit h soft wheat flour set later (5.8 min) during baking than those made w ith hard wheat flour (5.1 min). The differences in set time within coo kies made with various hard wheat flours or within cookies made with v arious soft wheat flours appeared to be affected by flour protein cont ent. However, other factors also affected the difference in set time b etween cookies made with hard wheat and soft wheat flours. Cookies mad e with soft wheat flour spread at a faster rate (7.8 mm/min) than thos e made with hard wheat flour (4.6 mm/min). The level of soluble starch in the flour appeared to cause the difference in spread rate between cookies made with hard wheat and soft wheat flour. The higher level of soluble starch in hard wheat flour (0.352 +/- 0.008%) than in soft wh eat flour (0.152 +/- 0.030%) increased dough viscosity, thus the sprea d rate was slower. However, soluble starch content did not explain the differences in spread rate within cookies made with various hard whea t flours or within cookies made with various soft wheat flours.