Red Seaweed-Derived Phycobiliproteins: Marine Bioactive Colorants with Functional Health Properties.

Color is a critical sensory attribute of foods that strongly influences consumer perception, acceptance, and purchasing decisions. As health-oriented consumption increases, natural pigments are progressively replacing synthetic colorants. Red algal phycobiliproteins (PBPs) have gained attention in related industries for their vivid water-soluble colors and potential health-promoting properties. Phycoerythrin (PE), phycocyanin (PC), and allophycocyanin (APC) are key pigment proteins responsible for their characteristic coloration. However, variations in algal species, season, and cultivation environments make PBP composition, yield, and quality difficult to standardize. This review summarizes red algal PBPs, covering algal sources, extraction and purification, physicochemical properties, biological functions, regulatory frameworks, and future directions. Major red seaweed sources, PBP types, and extraction strategies are compared, with cyanobacterial PBP studies incorporated where direct red algal evidence is limited. Evidence suggests that red algal PBPs are promising for clean-label, water-based, and mildly processed foods, including beverages, dairy products, confectionery, and meat alternatives, but their application is constrained by sensitivity to heat, light, oxygen, and pH. Beyond coloration, PBPs exhibit antioxidant, anti-inflammatory, anticancer, antibacterial, and metabolic health-promoting activities. Overall, red algal PBPs have considerable potential as dual-function ingredients, although commercialization requires advances in raw material standardization, stability-enhancement strategies, process optimization, clinical validation, and regulatory harmonization.