Abstract:

The extraction of alkali-soluble polysaccharides from the gonad of Sepia lycidas was investigated, and the
antioxidant activity, moisture absorption and retention capacities of the extracted polysaccharides were evaluated. The
optimal extraction conditions were determined as follows: NaOH concentration, 0.3 mol/L; solid/liquid ratio, 1:40; extraction
time, 3 h; and extraction temperature, 80 ℃, respectively. Under these conditions, the extraction yield of polysaccharides
was 7.697%. Antioxidant assays showed that the polysaccharides possessed good radical scavenging activity against
hydroxyl and DPPH radicals in a marked dose-dependent manner. Moisture absorption capacity of Sepia lycidas gonad
polysaccharides was better than that of chitosan, polyethylene glycol 6000 and other conventional humectants, and moisture
retention capacity was close to that of chitosan, polyethylene glycol 6000 and glycerol. The moisture absorption and
retention capacity of Sepia lycidas gonad polysaccharides were better than those of the polysaccharides from Perna viridis,
Crassostrea rivularis and other marine animals. These results clearly established the possibility that Sepia lycidas gonad
polysaccharides could be effectively employed as a natural antioxidant and moisturizer.

Key words: Sepia lycidas gonad, polysaccharides, antioxidant activity, moisture absorption, moisture retention