Antioxidant and Anti‐Inflammatory Activities of Enzymatic Hydrolysates From Gracilaria tenuistipitata Phycobiliproteins

Bioactive peptides (BAPs) derived from dietary proteins are increasingly recognized for their functional and therapeutic properties, making them promising candidates for functional foods and nutraceuticals. In this study, phycobiliproteins (PBPs), the major pigment proteins responsible for the vibrant coloration in the red alga Gracilaria tenuistipitata , were enzymatically hydrolyzed to generate BAPs. The antioxidant and anti‐inflammatory potential of the resulting BAPs was further investigated. PBPs were extracted from G. tenuistipitata using phosphate buffer solution (PBS) with repeated freeze–thaw cycles, followed by partial purification through isoelectric precipitation at pH 4. The PBPs were then subjected to in vitro enzymatic hydrolysis with various digestive enzymes, including α‐chymotrypsin, trypsin, pepsin, and their combinations, to produce BAPs. In vitro antioxidant (DPPH and ABTS scavenging) and anti‐inflammatory (trypsin and hemolysis inhibition) assays were conducted to determine the bioactivities of the resulting hydrolysates. Isoelectric precipitation yielded 1.75 and 1.72 mg/g dry weight (DW) of phycoerythrin (PE) and phycocyanin (PC), respectively, with purity indices improving significantly (PE: 0.7, PC: 0.61, PBP: 1.31) compared to crude PBPs (PE: 0.63, PC: 0.5, PBP: 1.13). The combined hydrolysate exhibited the highest antioxidant activity (DPPH and ABTS scavenging capacities of 44.77 ± 1.12 and 71.10 ± 0.77 μmol TE/g DW, respectively), compared with undigested PBPs. Additionally, the hydrolysates displayed strong anti‐inflammatory effects, with the combined hydrolysate showing higher trypsin inhibition (41.35 ± 0.69 mg QE/g DW) than undigested PBPs (27.01 ± 2.27 mg QE/g DW), while trypsin hydrolysate showed greater hemolysis inhibition (259.36 ± 5.78 mg DSE/g DW) than undigested PBPs (25.25 ± 5.8 mg DSE/g DW). Together, these results underscore the potential of enzymatically derived BAPs from G. tenuistipitata PBPs as natural antioxidants and anti‐inflammatory agents, with promising applications in functional food and nutraceutical development.