Extraction, Enrichment, Characterization, and Antioxidant Activities of Sargassum fusiforme Polyphenols

This study investigated the extraction, enrichment, characterization, and antioxidant activities of Sargassum fusiforme polyphenols (SFPs). The optimal extraction process conditions of SFPs are as follows: an ethanol volume fraction of 28%, a liquid–solid ratio of 29 mL/g, an extraction temperature of 80 °C, and an extraction time of 3.2 h. After enrichment by D101 macroporous resin, the purity of SFPs increased from 1.20 ± 0.08% to 10.78 ± 0.25%, increasing by approximately 8 times. SFPs were mainly composed of polyphenols, flavonoids, and polysaccharides. Furthermore, after identification by HPLC-QQK-ESI-MS/MS, they were found to contain 11 phlorotannins (mainly of the fuhalol type), 2 flavonoids, etc. In three antioxidant evaluation systems (DPPH free radical scavenging ability, reducing power, and total antioxidant capacity), the enriched SFPs all exhibited superior activities compared to tea polyphenols. The research results provide a theoretical basis and experimental evidence for the development of a new type of food preservative based on SFPs.