A study of the effects of water content on the compaction behaviour of breakfast cereal flakes

Wheat breakfast flakes were compacted in a cylindrical geometry using two different techniques and the volume measured as a function of applied pressure from 100 Pa to 85 MPa. The effect of water content, in the range 4 to 18% (wet weight basis), on the compaction behaviour of the flakes was examined for pressures from 1 to 85 MPa. The data were analysed using different relationships between density and applied pressure in accordance with Peleg, Kawakita and Heckel. The Heckel deformation stress decreased as the water content increased up to 12% and became inaccurate at 18% water. The Peleg compressibility and Kawakita yield stress only showed a marked decrease from 12 to 18% water. Collectively, these results agree qualitatively with other observations of the decrease in stiffness of single flakes over this water content range.