Résumé
Pulse legumes (pea, lentil, faba bean) are excellent source of proteins (20-30% db), dietary fibers (10-30%), and starch (40-55%). The formulation of gluten-free extruded snacks made entirely from pulse legumes is an interesting way to introduce legumes to young people. Due to the reactivity of protein components under thermomechanical treatment, extrusion can produce cellular structures with various texture and starch-protein composite morphology. In turn, the morphology of parietal material governs masticatory performances. For the first time, the interaction coefficient between bolus and saliva was determined by taking into account multi-scale structure of high-protein solid foams. The pea flour was extruded using a twin-screw extruder to obtain solid foams adapted to human mastication. Some samples were selected for in-vitro chewing by mapping the main properties: density, cellular architecture, texture, water absorption index (WAI) of starch and solubility of protein aggregates linked by S-S bonds in the dithiothreitol (DTE) using Principal Component Analysis. The boluses were collected at 3 chewing steps, representing different chewing times (t) until swallowing. The size distribution of bolus fragments was determined by imaging technique. Bolus consistency and water (“saliva”) uptake were determined by an adapted capillary rheometer, and gravimetric method, respectively. For all samples, the bolus viscosity exhibited shear thinning behaviour and it decreased with chewing time. Bolus flow index was quite constant for all chewing conditions and samples. However, bolus consistency index was correlated negatively to bolus water uptake (∆W) through a plasticization coefficient. Furthermore, ∆W could be predicted from theoretical salivary flow and median particle size. The model parameters depending on foams absorption properties could be expressed in function of WAI and protein solubility in DTE. The results will enrich the database for mechanistic modelling of proteinaceous solid foams chewing.