EFFECT OF STEEPING CONDITIONS ON WET-MILLING CHARACTERISTICS OF HARD RED WINTER-WHEAT

A batch-wise small-scale wet-processing laboratory for whole wheat ker nel has been designed and constructed to produce wheat starch and glut en from wheat grains. Hard red winter wheat kernels were steeped in th ree steeping media: SO2 solution, lactic acid, and hydrochloric acid. Acid concentrations of 0.1, 0.3, and 0.5%, were used for SO2 solutions and hydrochloric acid, and 0.1, 0.6, and 3.0% for lactic acid. After 16, 20, and 24 hr of steeping, the wheat was wet-milled. Yields and pr otein contents of wet-milling fractions were compared. Both high conce ntration of steeping media and long steeping time increased the starch yield and decreased the protein contents of the starch. However, the steeping time and acid concentration could be reduced from 24 to 20 hr and from 0.5 to 0.3%, respectively, without any statistically signifi cant difference in starch yields or protein contents of the starch. Co nsistency and color of the starch were affected by both steeping time and acid concentrations of steeping media.