Alkaline modification of carrageenans. III. Use of mild alkaline media and high ionic strengths

MARINA CIANCIA; MARÍA C. MATULEWICZ; ALBERTO S. CEREZO

CARBOHYDRATE POLYMERS

Elsevier Science, Ltd.

Lugar: Oxford, Gran Bretaña; Año: 1997 vol. 32 p. 293 - 295

0144-8617

The cyclization reaction (formation of 3,6-anhydro-á-D-galactose and 3,6-anhydro-á-D-galactose 2-sulfate units from á-D-galactose 6-sulfate and 2,6-disulfate residues, respectively) of carrageenans follows a pseudo-first-order kinetics. This reaction can be carried out, at reasonable rates, in sodium hydroxide solutions less concentrated than those usually employed or by using a milder base such as sodium carbonate. Rate constants were also determined at a fixed sodium hydroxide concentration but using different ionic strengths. No specific salt effects were observed at a given sodium hydroxide concentration and ionic strength.