Preparation of Nano-liposomes Carrying Phycobiliprotein Extracted from Red Algae (Gracilaria gracilis) with Chitosan Polymer Coating: Evaluation of Physicochemical, Antioxidant and Antimicrobial Properties

Encapsulation in liposome structure can be used as a protective carrier system for bioactive compounds during processing and storage under different conditions. Phycobiliproteins (PBPs) extracted from algae with antioxidant, antimicrobial, anti-cancer and anti-inflammatory properties can be applied to produce raw materials for functional foods. Therefore, in the present study, phycobiliprotein pigment was extracted from Gracilaria algae and the amounts of pigment was investigated. Also, nanoliposomes containing PBPs coated by chitosan (0, 0.5, 1 and 1.5%) were prepared and their physicochemical properties, antioxidant and antimicrobial activity were evaluated. The mean diameter of nanoliposomes and Polydispersity index (PDI) ranged from 336.9 to 577.7 nm and 0.25 to 0.28 in nanocarriers, respectively. The highest values of nanoliposome encapsulation efficiency of PBPs (83.98%) were obtained under optimal conditions in nanoliposomes with 1.5% chitosan coating. The results showed that the antimicrobial activity of the treatments increased significantly after encapsulation in the nanoliposome. In addition, the antioxidant activity of PBPs increased significantly after nanoencapsulation in liposomes. So that the EC50 level decreased to 81.27 and 107.67 ppm in DPPH and ABTS tests in nanoliposomes with 1.5% chitosan coating, respectively. Based on the findings of this study, it can be realized that nanocoating with chitosan effectively increases its stability, antimicrobial and antioxidant properties. Therefore, in order to increase the stability of natural compounds during different processes, it is recommended.