Physical and textural properties of biscuits containing jet milled rye and barley flour.

The biscuit-making performance of flour depends on both its botanical source and particle size. Several quality parameters of biscuits produced by partial replacement of wheat flour by barley and rye flours at 0, 10, 20, 30 and 40% were measured. Moreover, in order to investigate the effect of particle size, a commercial and two jet milled finer samples of both rye and barley flours were used. For most of the composite flours, the level of substitution was not statistically significant for the weight and the spread ratio of the biscuits. Biscuits with composite flours were softer and darker than the control biscuit (100% wheat flour). In addition, their total phenolics content and antioxidant activity were greater. Among composite flour biscuits, the finer barley flour biscuits were harder than those with the commercial flour. Moreover, as rye flour is darker than wheat and barley flours, rye biscuits were the darker of all. Porosity, bulk and true densities were affected by the particle size of the substitute flours.