DETERMINATION OF AMYLOSE BY DIFFERENTIAL SCANNING CALORIMETRY

A differential scanning calorimetry (DSC) method for the determination of amylose as its amylose-L-alpha-lysophosphatidylcholine (LPC) compl ex is described. Potato amylose/amylopectin mixtures covering the rang e of 0-95% amylose were heated in the presence of LPC, cooled and then reheated to follow melting of the amylose-LPC complexes formed during the cooling phase. A linear relationship (r = 0.98) was obtained betw een the amylose content of the mixtures and the enthalpies of the amyl ose-lipid complexes. This linear calibration was used to predict the a mylose content of various native starches, rice flours, wheat flour, d urum wheat semolina, and lyophilized raw potato on the basis of the me lting enthalpy of their amylose-LPC complexes. Except for the potato s amples, amylose contents determined by the DSC method were in good agr eement with those obtained from a colorimetric assay.