Composite solutions of Phycocyanin and chitosan extend oyster shelf life.

Phycocyanin (PC), a blue antioxidant and anti-inflammatory pigment, was combined with 2.5 % chitosan (CTS) to form stable composite solutions. This study aimed to develop a CTS-PC composite solution with enhanced antioxidant and antimicrobial properties to improve oyster preservation. Structural compatibility was confirmed through scanning electron microscopy and X-ray diffraction. Viscosity and contact angle analyses demonstrated encapsulation and barrier properties. Fourier-transform infrared spectroscopy, circular dichroism, zeta potential, and particle size analyses revealed that hydrogen bonding, hydrophobic interactions, and electrostatic forces contributed to stability. PC enhanced hydrophobicity and antioxidant capacity, and the 0.05 % PC/CTS solution exhibited the best strongest inhibition against Pseudomonas aeruginosa (19.14 ± 0.08 mm). Immersion extended oyster shelf life from 4 days (control) to 12 days (0.1 % PC/CTS), outperforming the commercial preservative (6 days). These findings highlight the potential of this safe, eco-friendly preservation strategy for oysters and other chilled aquatic products.