Enhancing vitamin D bioaccessibility: Unveiling hydrophobic interactions in soybean protein isolate and vitamin D binding via an infant in vitro digestion model.

In the domain of infant nutrition, optimizing the absorption of crucial nutrients such as vitamin D (VD) is paramount. This study harnessed dynamic-high-pressure microfluidization (DHPM) on soybean protein isolate (SPI) to engineer SPI-VD nanoparticles for fortifying yogurt. Characterized by notable binding affinity (K = 0.166 × 10 L·mol) at 80 MPa and significant surface hydrophobicity (H = 3494), these nanoparticles demonstrated promising attributes through molecular simulations. During simulated infant digestion, the 80 MPa DHPM-treated nanoparticles showcased an impressive 74.4% VD bioaccessibility, delineating the pivotal roles of hydrophobicity, bioaccessibility, and micellization dynamics. Noteworthy was their traversal through the gastrointestinal tract, illuminating bile salts' crucial function in facilitating VD re-encapsulation, thereby mitigating crystallization and augmenting absorption. Moreover, DHPM treatment imparted enhancements in nanoparticle integrity and hydrophobic properties, consequently amplifying VD bioavailability. This investigation underscores the potential of SPI-VD nanoparticles in bolstering VD absorption, thereby furnishing invaluable insights for tailored infant nutrition formulations.