Enzymatic Hydrolysates from Fucus vesiculosus: Optimal Process, Chemical Profile and Bioactivity

Fucus vesiculosus (FV) is a brown macroalga rich in bioactive compounds with significant industrial potential. This study aimed to produce enzyme-assisted water-soluble hydrolysates from FV with optimized antioxidant activity using Box-Behnken experimental designs. Two extraction methods were evaluated: cellulase alone (FVc) and a combination of cellulase and alcalase (FVca). The optimization focused on enzyme concentration, temperature, and incubation time, measuring extraction yield, total phenolic content as determined by the Folin-Ciocalteu assay (non-specific reducing capacity index, FC-derived TPC), total antioxidant capacity (TAC), and oxygen radical absorbance capacity (ORAC). Results demonstrated that the combined dual-enzyme (FVca) treatment was highly efficient, simultaneously maximizing the extraction yield (39.41%) and the overall reducing capacity (TAC of 142.80 µmol TE/g, ORAC of 477.64 µmol TE/g, and a FC-derived TPC of 252.57 mg GAE/g). Due to its higher potential, FVca was further characterized, revealing a rich profile of essential amino acids, low-molecular-weight peptides, and a diverse phenolic profile, dominated by phloroglucinol (6.23 mg/g). In addition, the FVca hydrolysate demonstrated severe abiotic interference with the redox viability assay at 10 mg/mL in Caco-2 human colorectal adenocarcinoma cell cultures. These findings highlight that combining cellulase and alcalase effectively solubilizes key bioactive compounds, yielding a hydrolysate highly promising for industrial and biotechnological applications.