Antioxidant properties of dried product of ‘haba-nori’, an edible brown alga, Petalonia binghamiae (J. Agaradh) Vinogradova

Dried ‘haba-nori’ Petalonia binghamiae, a brown alga, is a traditional food in the fisheries towns in Japan. To determine the antioxidant properties of the dried P. binghamiae, assays for antioxidant activities, including ferrous-reducing power, ferrous ion chelating, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and scavenging of a superoxide anion radical-generated by non-enzymatic system were tested in this study. A water extract solution contained total phenols at about 75 μmol phloroglucinol equivalents/g dry sample and showed strong antioxidant activities in the reducing power, DPPH radical and superoxide anion radical scavenging assays. The antioxidant activities were detected in high-molecular (>100 kDa), 10–30 kDa, and low-molecular (<5 kDa) fractions and were correlated with, not only phenolic compounds, but also brown compounds. The radical- scavenging activities were increased by heat treatment at 121 °C for 1 h. These results suggest that P. binghamiae is both a useful seafood and a healthy food with antioxidant activity.