Molecular characterization of starch by SEC: Dependance of the performances on the amylopectin content

The solubility of starch samples with different amylose/amylopectin ratios was investigated in NaOH and aqueous DMSO solutions. The decrease in solubility when the amylopectin content increases was clearly demonstrated. SEC experiments were performed using KOH 0.001 N as it was found to be better than the other aqueous solvents investigated. Even when the sample solubility was found to be high, SEC experiments showed the occurrence of some aggregation as a result of the retrogradation process. This phenomenon is undesirable for quantitative use of SEC and could not be diminished by the use of various additives. This paper demonstrates that no aqueous solvent tested is suitable for characterizing starch amylopectin and that the use of this technique has to be limited to the characterization of the amylose component of starch. (C) 1997 Elsevier Science Ltd.