Oral processing and bolus properties drive the dynamics of salty and texture perceptions of bread

- Relationships between oral processing, bolus and sensory properties were determined.
- Bread structure had a high impact on the dynamics of salty and texture perception.
- Changes in hydration and bolus rheology were observed during oral processing.
- Boluses G′ and G″ do not seem to be key parameters to trigger swallowing.
- Large inter-individual differences exist regarding subjects' masticatory behaviors.

During food consumption, complex oral processing occurs to progressively transform a solid food into a food bolus, ready to be swallowed. Bolus formation is an important step, not only because it prepares the food product for digestion, but also because it contributes to sensory perception. Using bread as a model food, the aim of this work was to identify the key mechanisms of oral processing for salty and texture perceptions in relation to food breakdown in the mouth. For this purpose, three model breads with the same salt content were prepared, varying in structure and/or composition. The dynamics of bolus formation and of sensory properties during consumption were characterized. Despite inter-individual differences observed on bolus properties, results showed that the three breads displayed different dynamic sensory profiles. Denser bread was perceived as being less salty and displayed a less complex texture perception sequence. For all of the breads, bolus hydration increased slowly and both G′ and G″ moduli decreased during oral processing (from the beginning of mastication until swallowing time). The G′ and G″ values of the dense bread at swallowing were significantly higher than those obtained for the two other breads, suggesting that bolus viscoelasticity is not a key parameter to trigger swallowing. However, results showed that panelists exhibited different masticatory and hydration behaviors regarding both the kinetics of bolus formation and the final bolus properties. This study contributes to a better understanding of food oral processing and the impact of bolus formation on sensory properties.