Core-shell nanofiber encapsulation of α-linolenic acid via peanut protein isolate-pullulan Maillard conjugates:...

Herein, core-shell nanofibers loaded with α-linolenic acid (ALA), a highly unsaturated polyunsaturated fatty acid (PUFA) sensitive to oxygen, were fabricated by emulsion electrospinning using peanut protein isolate-pullulan (PPI-PUL) Maillard conjugates as emulsion stabilizers. Emulsion electrospinning enables the encapsulation and provides a protective barrier and efficient delivery. This work aims to elucidate the relationship between the covalent grafting and emulsion interfacial viscoelasticity, lipid protection, and bioaccessibility. These results showed that the conjugates prepared at 80 °C (PU11H) exhibited the highest degree of grafting (13.48%), an emulsifying activity index of 462.89 m²/g, and the smallest ALA droplet size (0.839 μm). These interfacial properties suppressed droplet mobility and delayed phase separation, so the bead-free nanofiber with a core-shell structure was obtained after electrospinning. PU11H achieved the highest encapsulation efficiency (>95%), and showed the lowest POV and TBARS among all samples after 9 days at 40 °C, confirming that higher grafting density improved the oxidative stability. In vitro digestion indicated that PU11H had a final bioaccessibility of 63.5% in the intestinal phase (vs 25.5% for free ALA). Overall, these findings indicate that controlling the degree of grafting of protein-Maillard conjugates offers facile strategies to enhance oxidative stability and intestinal delivery of PUFAs.