Separation and characterization of linear glucans debranched from normal corn, potato and sweet potato starches

Debranched starches (DBSs) are widely used in food, pharmaceuticals, and health products. The purpose of this study is to separate fractions of debranched normal starch with different degrees of polymerization (DP). Five fractions were obtained by the ethanol precipitation fractionation method with different water-to-ethanol ratios, including a very long DBSp (p: precipitate), long DBSp1.5 (p1.5: water/ethanol = 1:1.5 precipitate), moderately long DBSp4 (p4: water/ethanol = 1:4 precipitate), short DBSs1.5 (s1.5: water/ethanol = 1:1.5 supernatant), and very short DBSs4 (s4: water/ethanol = 1:4 supernatant). The main peak DP values of different fractions of debranched normal corn starch were 24.41, 16.74, 13.70, 7.77, and 6.09, respectively. The fractions of DBSs from potato and sweet potato starches had larger molecular weights. The crystalline structure of DBSp and DPSp4 was B-type while that of DBSp1.5 was A-type. DBSs with different properties could be obtained from normal starch by the green and simple aqueous ethanol precipitation method.