Adhesion properties of wheat-based particles

• The adhesion properties of starch, protein, and arabinoxylan are evaluated by AFM.
• The local contact radius is a key parameter in interpreting the interactions.
• AFM is more sensitive for hydrophobic wheat components.
• Protein has higher interactions than starch, and arabinoxylan.
• The interactions with starch and arabinoxylan are similar whatever the surface.

Specific AFM analytical methods were tested to the surface evaluation of wheat powders at micrometric scale in dry conditions. The objective was to evaluate the adhesion properties of particles based on the main wheat endosperm components (starch, protein, and arabinoxylan) that are characterized by large diversity in terms of chemical composition and particle characteristics. Experiments were conducted by using the force spectroscopy mode to determine interactions generated by the surfaces of particles that were glued on AFM tips, and two reference flat and smooth surfaces, a glass and a polysine slide. Particular care has been devoted to characterize the surfaces in contact since local contact radius is a key parameter in the interpretation of the interactions. The statistical analysis of the normalized adhesion forces have shown the sensitivity of the AFM technique for hydrophobic wheat components and their correlation with the surface tension of the particles.