Cereal Chem 69:626-632   |  VIEW ARTICLE

Starch-Lipid Interactions and Formation of Resistant Starch in High-Amylose Barley.

J. Szczodrak and Y. Pomeranz. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Starch was isolated and purified from a barley selection with 42.3% amylose in the starch. The white- and brown-layer starch fractions differed in chemical composition and endothermic properties; amylose was higher in the starch of the brown layer (49.3%) than in the starch of the white layer (43.5%). After being autoclaved for 1 hr at 121 C, the starches were reacted during cooling from 100 C to ambient temperature with sodium stearoyl lactylate, distilled monoglycerides, diacetyl tartaric acid esters of mono-diglycerides (DATEM), and ethoxylated monoglycerides. Formation of amylose-lipid complexes was indicated by peaks in differential scanning calorimetry thermograms at temperatures from 100 to 112 C. Endothermic transitions from 154 to 162 C (mean, 158 C) reflected the presence of crystallized amylose. Yields of enzyme-resistant starch (RS) from a single autoclaving-cooling cycle were 7.1 and 4.0% for the white- and brown-layer starches, respectively. Those yields decreased to 0.7-5.3 and 0.7-2.1%, respectively, when RS was prepared after the starches were complexed with the various emulsifiers. Complexes between distilled monoglycerides, DATEM, and ethoxylated monoglycerides and amylose from the brown starch layer attained relatively higher values of melting enthalpies than those from the white layer. It is postulated that amylose crystallization (as measured by enthalpies of the 158 C endotherm) that is involved in the formation of RS is competitively affected by the complexation of amylose with lipids. The effects of complexation on yields and enthalpy of RS from high-amylose maize and barley starches differed widely.