Modifications of mechanical properties were linked with variations of cell size and cell wall structure
(Figure 2).
x Without addition of fibers (F0-), only minor modifications of porosity and cell size are observed when the whole grain content increases while the cell wall thickness increases significantly between
40% and 60% WG content.
x Conversely, adding fibers decreases the expansion of extruded cereals and thus the cell size and the porosity decreases while the thickness of cell wall globally increases, in agreement with the increase of maximum force observed.