Nanoencapsulated vitamin D3 as an innovative strategy for fortifying vegetarian sausages: physicochemical evaluation, retention, and in vitro bioaccessibility

Vitamin D deficiency is currently a critical public health problem worldwide, especially among vegetarian and vegan populations, driving the search for food fortification strategies. The aim of this research was to develop vegetarian sausages fortified with nanoencapsulated vitamin D3 and evaluate their physicochemical properties, as well as the in vitro retention and bioaccessibility of the micronutrient. The vegetarian sausages were formulated with either free vitamin D3 (FVD3) or nanoencapsulated vitamin D3 (NVD3). Evaluations included pH, instrumental color, texture profile analysis (TPA), and lipid oxidation (TBARS). Vitamin D3 retention was also assessed by HPLC, and its in vitro bioaccessibility was evaluated. The incorporation of the nanoemulsion increased pH and lightness (L*), while reducing elasticity and chewiness. No differences in lipid oxidation were observed between treatments (p > 0.05). The NVD3 treatment showed retention exceeding 86%, significantly higher (p < 0.05) than the 38% observed with FVD3, and also exhibited superior in vitro bioaccessibility. These results demonstrate that nanoencapsulation is an innovative and effective strategy for improving both the technological stability and in vitro bioaccessibility of vitamin D3 in meat analogs, offering a promising approach for the development of functional foods targeting vegetarian consumers.