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The oral destructuration of food leads to the formation of a bolus that can be swallowed. The rheological properties of artificial boluses of cereal foods are determined here over a wide range of stresses and strains, in the range of water content encountered during chewing.

For the four foods tested, sponge cake or extruded cereal product enriched or not with legume proteins, the hydrated boluses show behavior similar to that of a gel at low strain, and to that of a yield stress fluid at high strain. Boluses can thus be characterized by two essential rheological properties: the characteristic stress at transition to flow and flow consistency.

The decrease of these properties with increasing water content, fitted by an exponential function, is used to determine a coefficient of interaction of the food with water α. These α values, thus calculated, are higher for pea-based extrusions (α ≥15), than for sponge cake (α ≤15). When compared to those found for real boluses, findings suggest that α allows characterization of the interaction of the food with saliva. Thus, the same approach could also be applied to other foods to account for their interaction with saliva and aid in the design of specific diets.