3D-printable docosahexaenoic acid-rich algal oil emulsion gels functionalized by multi-shaped starch nanorods

The poor stability and low bioavailability of docosahexaenoic acid (DHA) from algal oil restrict its application in functional foods, particularly in three-dimensional (3D) printing systems where both printing performance and lipid protection are required. Here, starch nanorods (SNRs) with prismatic, ellipsoidal, and spindle-shaped morphologies were prepared and employed to stabilize DHA-rich algal oil emulsion gels. The influences of SNR shape and concentration on emulsion stability, gel structure, rheology, and printability were evaluated. At 4 % (w/v), spindle-shaped SNRs from normal corn starch (labeled as N20) achieved nearly complete oil encapsulation, significantly suppressed water mobility and reinforced gel elasticity, resulting in pronounced shear-thinning and excellent self-supporting capacity. The N20-stabilized gel exhibited superior printing fidelity, forming stable 3D constructs without oil leakage. When incorporated into plant-based tuna analogues, the emulsion gel yielded products closely resembling real tuna in texture and color, while enriching DHA content in fatty acids to 43.54 %, far exceeding that of commercial tuna. These findings highlight the critical role of particle shape in modulating interfacial stabilization and multiscale gel properties, providing a practical route for designing functional inks in food 3D printing for developing plant-based seafood with both structural and nutritional enhancements.