MECHANICAL-PROPERTIES OF WHEAT

Fundamental mechanical properties of the wheat kernel were characterized for five different wheat classes. An Instron testing machine was used to perform a compression test on wheat slices. Wheat slices were prepared by cutting off both ends of the wheat kernel. A cross-sectional area of the wheat slices was measured using a commercial image processing system. An offset yield of 0.2 % was introduced for determining the yield point for wheat and used to determine yield stress, yield strain, modulus of deformability, and energy to yield point. To determine the effect of sample location, each kernel of hard red spring and soft red winter wheats was cut into two slices (germ end and brush end). No significant differences, a = 0.05, were found in values of the physical properties for germ-end and brush-end samples. In general, the four properties increased as loading rate increased up to a 100 mm/min and decreased thereafter The mean values of yield stress for all five wheat classes decreased as moisture content increased. Soft wheat samples had generally lower modulus of deformability values.