Physicochemical properties and bioactivity of brown seaweed fucoidan prepared by ultra high pressure-assisted enzyme treatment

The effects of ultra-high pressure (UHF 100 MPa, 40, 24 h) processing and enzyme treatment on the physicochemical properties and anticoagulant activity of fucoidan obtained from Undaria pinnatifida sporophyll (UPS) were investigated. Crude UPS fucoidan (F-UPS) with an average MW of 877 kDa was slightly depolymerized by UHP-assisted Tunicase treatment, yielding fucoidan with a lower MW (600-800 kDa). UHP-enzyme treatment decreased the sulfate, fucose and galactose contents of F-UPS but increased its glucose content. From FT-IR spectrum, UHP-enzyme treatment was found not to cause a structural change on S = O and C-O-S. After UHP-enzyme treatment, the sulfate content and average MW of F-UPS decreased with the increase of Tunicase concentration. It was found that among the UHP-enzyme-treated fucoidans, F-UPS-T0.3-U (Tunicase 0.3% treatment+UHP treatment) possessed the highest anticoagulant activity. F-UPS-T0.3-U appeared to inhibit blood coagulation via intrinsic pathway. With the increase of sulfate content in F-UPS, activated partial thromboplastin time (APTT) and thrombin time (TT) showed a tendency of increase. APTT and TT had the highest values in F-UPS-T0.3-U in which the sulfate concentration was 24%, but on the contrary decreased at a sulfate concentration of above 24%. This result indicates that there is an optimum sulfate concentration for the anticoagulant activity of fucoidan. Consequently, UHP-assisted enzymatic treatment was found to be helpful for the improvement of anticoagulant activities of fucoidan.