Cereal Chem 67:240- 246   |  VIEW ARTICLE

Viscoelastic Behavior of Aging Starch Gels: Effects of Concentration, Temperature, and Starch Hydrolysates on Network Properties.

C. G. Biliaderis and J. Zawistowski. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

The time-dependent changes in network properties of aqueous starch, amylose, and waxy maize starch (amylopectin) gels were studied by small-strain oscillatory shear measurements (0.2 Hz and 2% strain) and differential scanning calorimetry. In the concentration range of 1.9-8.8%, the storage modulus (G') of amylose gels increased rapidly in the early stages but little change on long-term storage. Amylose gels were also less sensitive to storage temperatures than amylopectin and wheat starch gels. The molecular origin of waxy maize gel network development appears to sie in the crystallization of the short chains of the amylopectin molecule, as probed by differential scanning calorimetry. Waxy maize starch gelation within 24 hr of storage occurred only at high polymer concentrations (greater than 20%, w/w). Data on the effect of temperature on gelation kinetics of this starch suggested that the overall process is nucleation controlled. Whereas small molecular weight starch hydrolysis products weakened the gel network of wheat starch gels (presumably via competitive inhibition of interchain associations between the exuded amylose chains) they enhanced the rigidity of waxy maize starch gels.