Textural aspects and digestibility of a high-protein dessert using INFOGEST's adult and older adult static in vitro digestion models.

Abstract

Protein-rich foods tailored to older adult's dietary needs, textures and digestive capabilities are essential to help mitigate sarcopenia and malnutrition. This study developed two high protein dulce de leche type of desserts that were enriched with whey protein isolate (WPI-DD) alone or in combination with whey protein hydrolysate (WPI + WPH-DD). Their texture, rheology and tribology were characterized against a conventional dulce de leche (control). Protein digestibility was assessed using INFOGEST's in vitro static digestions simulating the adult and older adult gastrointestinal tract (G.I.T). Amino acid profiling revealed an expected increase in total amino acid content 68.4 mg/g (control) to 183.9 and 188.11 mg/g product, with leucine increasing from 5.5 to 19.7 and 20.37 mg/g product, for WPI-DD and WPI + WPH-DD respectively. Both protein-enriched products had a lower firmness and viscoelastic moduli than the control. In the presence of saliva, WPI + WPH-DD showed higher friction coefficients in the boundary and mixed regimes than WPI-DD and the control, indicating reduced lubrication. Size-exclusion chromatography revealed lower gastric proteolysis in the older adult model, with whey proteins resisting pepsin hydrolysis in both age models. Small intestine proteolysis was highly efficient for the enriched desserts, with less pronounced age-related differences. The hydrolysate-containing formulation showed faster leucine release. Both whey-based formulations achieved >95 % protein digestibility, with digestible indispensable amino acid ratios (DIAAR%) ≥100 %, even under older adult conditions. Coupling INFOGEST's age-specific in vitro digestion models with texture, rheology and tribology profiling provides insights into designing food for older adults that meet both nutritional and textural needs.