The older adult population is greatly affected by malnutrition. This condition can arise from inappropriate micro and micronutrient intake, as well as due to experienced age-related changes. For instance, a significant number of older adults suffer from dysphagia. Thus, the development of foods with adequate consistency/viscosity are vital for overcome this condition. Within this framework, novel functional thickened drinks were developed and tailored for the older adult population, by using chia seed gum as the thickening agent enriched with vitamin D3loaded solid lipid nanoparticles (SLN). Rheological properties of different thickened drinks formulated with water, semi-skimmed milk or orange juice were optimized using a central composite rotational design. Results showed that SLN delivered high vitamin D3 encapsulation efficiency with high concentration (i.e., 32 IU/mg). The different drink matrices attained distinct rheological properties, being observed that the viscosity and consistency attained with the same thickening agent concentration was higher in more complex matrices. An optimized formulation containing the tolerable upper intake level (ca. 4000 IU) was selected to study the vitamin D3 release and bioaccessibility on older adults' population using a dynamic in vitro gastrointestinal digestion system. Once more, strong matrix effects were observed and significantly affected vitamin D3 release profile, bioaccessibility and recovery during the in vitro digestion. Additionally, the drinks enrichment with SLN-VitD3 did not display a negative effect on cells viability. The development of novel functional thickened drinks tailored for older adults could provide a safer swallowing and improved vitamin D3 intake.
