Degradation of Laminaria japonica fucoidan by hydrogen peroxide and antioxidant activities of the degradation products of different molecular weights

► The first study the relationship between reaction conditions of hydrogen peroxide hydrolysis and the Mws of Fucoidan degradation products. ► The first time choosing seven samples to study the relationship between the Mws and the antioxidant activities of the fucoidans. ► The relationship between Mws of fucoidans and their antioxidant activities is not simply linear.