Abstract

Wheat endosperm belongs to the broad class of cemented granular materials such as sedimentary rocks or geomaterials such as mortars or concrete. They have in common a texture composed of particles embedded in a solid matrix of variable volume and cohesion with the particles. Their heterogeneity can be described either in terms of the composition (phase volume fractions, contacts and bonds between the particles…) or in terms of transport properties such as force transmission which reflects the details of the composition.

In this talk, I present a cohesive granular model of the wheat endosperm involving a discrete phase composed of starch granules, a continuous phase representing the protein matrix and pores. The cohesion of the texture is governed by adherence between starch and protein, reflecting the biochemical nature of the interface, and the protein content that controls the connectivity between starch granules. The numerical model is employed to simulate the behaviour of samples with variable matrix volume fraction and particles–matrix adherence. Crack formation is analyzed in terms of particle damage as a function of matrix volume fraction and particle-matrix adherence. In the case of the grinding of wheat endosperm, the cracking regimes are associated with the hardness classes of soft, hard and durum wheat.