Combined process of high-pressure homogenization and hydrothermal extraction for the extraction of fucoidan with good antioxidant properties from Nemacystus decipients

Sulfated polysaccharides (fucoidan) were recovered from Nemacystus decipients using a combination of high pressure homogenization (HPH) and hydrothermal extraction process through employing different homogenization pressure (40-100 MPa) and cycle times (1-3). HPH treatment could result in a high fucoidan yield with preserving sulfate content and the optimal yield was 16.67 ± 0.36%, obtained from 70 MPa for 2 cycles' extraction. Chemical composition analysis, HPAEC, IR and HPSEC analysis were applied for characterization of extracted polysaccharides. The molecular weight of extracted fucoidan decreased with increasing extraction pressure. All fucoidan exhibited antioxidant activities as determined by DPPH radical scavenging, hydroxyl radical scavenging, and ferrous ion chelating ability as well as reducing power, among which fucoidan extracted at 70 MPa (HN2) possessed excellent antioxidant ability. This study shows that HPH can be used as an efficient means to assist extraction of fucoidan from seaweed and N. decipients could potentially be a raw resource for natural antioxidant.