Cereal Chem 68:172-177   |  VIEW ARTICLE

Thermal and Viscous Properties of Rye Starch Extracted from Different Varieties.

M. Gudmundsson and A.-C. Eliasson. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Thermal and viscous properties of rye starch extracted from different cultivars were studied and compared with gelatinization parameters and retrogradation of wheat and maize starches. Gelatinization parameters for the rye starches were shown to be lower than those for wheat starch but similar to those for oat starches (literature value). The transition of the amylose-lipid complex was low, which indicated a low lipid content in the starch. Retrogradation of the rye starch was quite low compared with that of wheat and maize starches despite the low lipid content. The viscous properties of the rye starches were investigated in the 60-90 C temperature interval. The rye starches increased in viscosity very differently with increasing temperature and differed in their end-viscosity values after 400 sec holding time at 90 C. The gelatinization parameters, retrogradation (enthalpy value after 14 days of storage), and viscosity (end value after 400 sec at 90 C) were correlated with other measured factors, such as falling number, gel volume, amylose leaching, and percentage of fissures on the surface of starch granules. Moderate to high correlation was found between gelatinization enthalpy and falling number, end viscosity, and percentage of fissures (0.64, -0.72, -0.95, respectively). Gelatinization temperature correlated moderately with falling number, end viscosity, and gel volume (0.61, -0.85, and -0.70, respectively). Falling number also had a moderately high-correlation with percentage of fissures and amylose leaching (-0.84 and 0.78). Retrogradation (enthalpy value after 14 days of storage) correlated highly with amylose leaching (0.90). End viscosity correlated highly with percentage of fissures and gel volume (0.91 and 0.79). These correlations helped considerably to explain the thermal and viscous properties of the rye starches investigated.