Abstract
Eucheuma muricatum mucilage which was extracted and purified after irradiation of the seaweed with γ-ray of 60Co formed a complex with I-3, and exhibited a new absorption band at 555 nm. The absorbancy observed at that time depended on the concentration of urea and on the temperature. The curves representing relations between absorbancy at 555 nm and the above factors have two inflection points. The fact that their inflection points shift toward the lower temperature side with the increase in urea concentration suggests that the coloring phenomenon may relate closely to the sol→←gel transition of the mucilage. It was also found that the absorbancy at 555 nm depended on the content of pyruvic acid residue in the same mucilages, the absorbancy decreased with the increase pyruvic acid residues, and that the steric hindrance caused by a sugar residue of large demension affected the stable from containing viscous polysaccharide.
