Red Macroalgae as Sources of Antioxidant and Multifunctional Ingredients for Functional Foods: A Biorefinery Approach

, exhibited strong hydrogen atom transfer-based antioxidant capacity, whereas ethanolic extracts demonstrated multifunctional activity, combining radical scavenging, metal chelation, and enzyme inhibition associated with neuroprotective and glycemic-regulation potential. Polysaccharide fractions contributed mainly to iron chelation and reducing capacity. Correlation analyses highlighted the complementary nature of antioxidant and bioactivity assays. Overall, these findings support the potential of Madeira red macroalgae as functional food ingredients and emphasize the importance of optimized biorefinery strategies to maximize nutritional and health-related benefits.