Fructose-grafted amylose and amylopectin

Amylose and amylopectin have been heated with sucrose in acidic methyl sulfoxide. The fructose oxocarbonium ion derived from sucrose was transferred as fructofuranosyl groups to O-6 of the glucans, giving fructoglucans containing up to 7.9% (amylose) and 5.8% (amylopectin) of fructose. The fructosyl units on amylose prevented retrogradation from aqueous solution, resulted in a less-blue iodine complex, and decreased the extent of degradation by amyloglucosidase. The addition of fructosyl units to amylopectin reduced the extent of its degradation by beta-amylase.