Cereal Chem. 70:163-170 | VIEW
Enzyme-Resistant Starch: Studies Using Differential Scanning Calorimetry.
L. Gruchala and Y. Pomeranz. Copyright 1993 by the American Association of Cereal Chemists, Inc.
Factors governing the formation of enzyme-resistant starch (RS) from high-amylose maize starch under laboratory conditions were investigated. Those factors studied included sample size, gel dimensions, number of heating-cooling cycles, and cooling conditions. Cooling to about 20 C produced RS with higher enthalpies than cooling to 4 C or freezing at about -20 C. Freeze-drying was not superior to oven-drying. Heating of resuspended RS increased enthalpies. RS could be stored at -20 C odor-free for at least eight months. A rancid odor developed within several weeks of storage at room temperature. Thermal characteristics of RS, as measured by differential scanning calorimetry (DSC), were sample-size-dependent. To determine the stability of RS, samples were preheated under conditions similar to those in baking bread: temperatures of 100 and 200 C, both dry and with water. Preheating RS, especially with water, at 200 C resulted in a disintegration of the RS. No significant changes in DSC characteristics took place during preheating at 100 C. The presence of gluten or wheat starch in RS blends (as they might exist in bread) reduced measurable DSC enthalpies.