Ultrasonically Engineered Probiotic Particles as the Sole Stabilizer for Fucoxanthin-Loaded High Internal Phase Pickering Emulsions: Stability and Functional Study

High internal phase Pickering emulsions (HIPPEs) are valued for their exceptional stability and versatility in delivering food bioactives. Here, we developed fucoxanthin (Fx)-loaded HIPPEs using ultrasonically engineered probiotic particles as the sole stabilizer and investigated their stabilization mechanism and functional characteristics. Ultrasonic power levels from 0 to 600 W were screened; at the optimal 450 W, the probiotic particles exhibited the lowest surface charge (-30.8 mV) and the highest three-phase contact angle (87.3°), promoting a dense film at the oil-water interface. This improved structural uniformity, rheological properties, and environmental stability. In vitro digestion simulations demonstrated that HIPPEs maintained structural integrity under gastric conditions and gradually disintegrated in the intestinal phase due to bile salts and lipase. This achieved a free fatty acid release rate of 81.3%, enhancing Fx bioaccessibility to 36.17%. Moreover, laser-assisted 3D printing technology accelerated curing by rapidly evaporating free water, further densifying the microstructure and enhancing the stability of printed structures. These findings highlight how ultrasonic engineering enhances the interfacial activity of probiotic particles, verifying their feasibility as a single stabilizer for functional HIPPEs. They also provide a novel strategy for using natural probiotics in food delivery systems and for efficient active ingredient encapsulation.