Cereal Chem. 73 (6):712-715 |
Mathematical Characterization of the Plasticizing and Antiplasticizing Effects of Fructose on Amylopectin (1).
Micha Peleg (2). (1) Contribution of the Massachusetts Agricultural Experiment Station, Amherst, MA. (2) Department of Food Science, Chenoweth Laboratory, University of Massachusetts, Amherst, MA 01003. E-mail: <firstname.lastname@example.org> Accepted July 24, 1996. Copyright 1996 by the American Association of Cereal Chemists, Inc.
Published data indicate that admixture of fructose to amylopectin increases the latter's stiffness but lowers its glass transition temperature range and makes the transition sharper. It also dramatically increases the plasticizing effect of absorbed moisture. These effects are quantified in terms of the parameters of a mathematical model based on Fermi's equation, which can describe mechanical changes at and around the glass transition of biopolymers, irrespective of whether it is sharp or broad. This model accounts for the mixture's stiffness dependency on both the fructose concentration and temperature, or moisture, with a single algebraic expression. It can also be used to create three-dimensional plots from which the combined effects of fructose and temperature, or moisture, can be viewed, and conditions of plasticization, or antiplasticization, be identified.