Najmeh Oliyaei, Nader Tanideh, Marzieh Moosavi‐Nasab
BACKGROUND: Ovalbumin-fucoidan (OF) complex nanoparticles were prepared for fucoxanthin encapsulation. The effects of polymer ratios (ovalbumin:fucoidan, 5:1, 2.5:1, 1:1, 1:2.5, 1:5 w/w) and pH values (3, 4.5, 6, 7, and 8) on complex coacervate formation were investigated to identify optimal conditions. The selected conditions were then applied for fucoxanthin encapsulation. RESULTS: The OF complex exhibited particle sizes of 200-265 nm. The zeta potentials were -24.67 ± 0.42 mV for fucoidan, -17.25 ± 0.39 mV for ovalbumin, and -3.47 ± 0.90 mV for the OF complex. At pH 3, the zeta potentials of fucoidan and ovalbumin were -9.80 ± 0.30 mV and 7.33 ± 0.21 mV, respectively, confirming electrostatic interactions between the oppositely charged polymers and the formation of complex coacervates. Turbidity measurements indicated that a 1:1 polymer ratio (ovalbumin:fucoidan, w/w) at pH 3 was optimal for complex formation (P < 0.05), and these conditions were selected for fucoxanthin encapsulation. The resulting nanoparticles achieved 88.33 ± 0.14% encapsulation efficiency, and the chemical and morphological characteristics of the polymers and coacervates reflected changes due to interactions and fucoxanthin incorporation. Fucoxanthin release reached 12.83 ± 0.12% in simulated gastric fluid (SGF) and 42.77 ± 0.4% in simulated intestinal fluid (SIF). CONCLUSION: This study suggests that OF complex nanoparticles are effective carrier for the encapsulation of hydrophobic compounds. © 2025 Society of Chemical Industry.