Chemical and Antioxidant Properties of Solvent and Enzyme-Assisted Extracts of <i>Fucus vesiculosus</i> and <i>Porphyra dioica</i>

Extraction strategies impact the efficiency and nature of extracted compounds. This work assessed the chemical composition and antioxidant capacity of ethanolic, hydroethanolic, and aqueous versus enzyme-assisted extracts (isolated or with the sequential use of alcalase^®, cellulase^®, and viscozyme^®) of the macroalgae <i>Fucus vesiculosus</i> (brown, <i>Phaeophyceae</i>) and <i>Porphyra dioica</i> (red, <i>Rhodophyta</i>. For both macroalgae, enzyme-assisted extraction (EAE) was the most efficient process compared to solvent-assisted extraction (SAE), independent of solvent. <i>Fucus vesiculosus</i> extraction yields were higher for EAE than for SAE (27.4% to 32.2% and 8.2% to 30.0%, respectively). Total phenolics content (TPC) was at least 10-fold higher in EAE extracts (229.2 to 311.3 GAE/g_extract) than in SAE (4.34 to 19.6 GAE/g_extract) counterparts and correlated well with antioxidant capacity (ABTS and ORAC methods), with EAE achieving values up to 8- and 2.6-fold higher than those achieved by SAE, respectively. <i>Porphyra dioica</i> followed <i>F. vesiculosus’s</i> trend for extraction yields (37.5% to 51.6% for EAE and 5.7% to 35.1% for SAE), TPC, although of a lower magnitude, (0.77 to 8.95 GAE/g_extract for SE and 9.37 to 14.73 GAE/g_extract for EAE), and antioxidant capacity. Aqueous extracts registered the highest DPPH values for both macroalgae, with 2.3 µmol TE/g_extract and 13.3 µmol TE/g_extract for <i>F. vesiculosus</i> and <i>P. dioica</i>, respectively. EAE was a more efficient process in the extraction of soluble protein and reducing sugars in comparison to SAE. Furthermore, an improved effect of enzyme-assisted combinations was observed for almost all analyzed parameters. This study shows the promising application of enzyme-assisted extraction for the extraction of valuable compounds from <i>F. vesiculosus</i> and <i>P.dioica</i>, making them excellent functional ingredients for a wide range of health and food industrial applications.