Solution properties of sodium alginate from brown seaweeds living along the coast of Japan. III. Molecular size distribution of alginic acid.

The molecular size distribution of alginic acid in seven species of brown seaweeds found along the coast of Japan was determined by sedimentation velocity method. All the differential distribution curves of sedimentation constant were symmetrical. The alginic acid prepared from “kajime” (Echlonia cava Kjellman) and from “oni-konbu” (Laminaria diabolica) showed a sharp size distribution. No clear correlation was found between the molecular size distribution, the content, and the yield of alginic acid, through the species examined.