Cereal Chem 55:936 - 944.  |  VIEW ARTICLE
Wheat Starch Gelatinization in Sugar Solutions. I. Sucrose: Microscopy and Viscosity Effects.

M. M. Bean and W. T. Yamazaki. Copyright 1978 by the American Association of Cereal Chemists, Inc. 

A photomicrographic technique was used to study swelling behavior of individual wheat starch granules heated in water and various sugar solutions. With the polarizer rotated slightly off extinction, birefringent and gelatinized granules could be photographed simultaneously. Granule diameters were measured from enlargements of photographs taken during heating and were plotted as ratios of the granule diameters at 50 C. A rapid increase in diameter occurred during and immediately after loss of birefringence, and coincided with the first-stage gelatinization exhibited by amylograph viscosity curves. The rapid swelling stages occurred at progressively higher temperatures and at faster rates as sugar concentration was increased to 60%, the highest used. Amylograph viscosities emphasized the delaying effects of sucrose on gelatinization of starch and demonstrated that only first-stage swelling may occur in 50% sucrose solution before the medium boils. Such results are applicable to layer-cake systems in which the level of sugar often equals that of water in the batter.