Instrumental Food-to-Bolus Transformation of Commercial Toddler-Oriented Finger Foods: An Exploratory Comparison

Commercial complementary finger foods vary widely in structure, yet conventional product categories provide limited information on how they transform during oral processing. This exploratory study characterized seven commercial toddler-oriented snacks using a multi-stage instrumental approach linking mechanical–acoustic fracture with saliva-mediated disintegration and hydrated-bolus mechanics. Products were assigned to provisional descriptive matrix categories: protein-based cellular, expanded starch-based cellular, and dense biscuit matrices. Three purposively selected exemplars—yogurt melts (P2), mini crackers (P4), and milk biscuits (P5)—were further evaluated by artificial saliva-mediated oral disintegration, dynamic instrumental mastication, rheology, and tribology. Dry-state hardness varied more than six-fold among the seven products (531.6–3426.3 g), with only partial correspondence between provisional matrix category and fracture profile. P2 showed rapid structural disruption, with largest core proportion decreasing from 98.9% to 18.5% by 30 s; P4 showed progressive disintegration and required the highest saliva-to-sample ratio for cohesive-bolus formation (2.5:1); and P5 retained coarse fragments and formed the bolus with the highest storage modulus (G′ = 616.6 Pa at 1 rad s−1). Despite rapid disintegration, P2 showed the highest initial DIM force (9.30 N) and highest integrated friction (nAUClog v = 0.154). These product-specific findings suggest associations between initial product characteristics and subsequent instrumental responses, with rankings varying across measurements. They do not establish class-wide pathways or physiological oral-processing performance.