Rheological Properties of Dispersions of Spherulites from Jet-Cooked High-Amylose Corn Starch and Fatty Acids

Authors: Byars, Jeffrey; Fanta, George; Felker, Frederick

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2008
Publication Date: 1/2/2009
Citation: Byars, J.A., Fanta, G.F., Felker, F.C. 2009. Rheological Properties of Dispersions of Spherulites from Jet-Cooked High-Amylose Corn Starch and Fatty Acids. Cereal Chemistry. 86(1):76-81.

Interpretive Summary: Excess steam jet cooking is a process that has been used at NCAUR to develop a number of important products. If a jet-cooked starch dispersion with added fatty acid is cooled quickly, the starch forms small, crystalline particles. This work shows that the resulting material can be used to form pastes that are smooth and flow easily. An understanding of the effects of the preparation method on the flow properties allows a range of new materials to be formed and opens new areas of application.

Technical Abstract: High amylose corn starch was cooked in an excess-steam jet cooker in the presence of 5% oleic or palmitic acid, based on amylose. The cooked product was rapidly cooled in an ice bath and then freeze dried or drum dried. Amylose was removed from solution by forming helical inclusion complexes with the fatty acid and the inclusion complexes formed sub-micron spherical particles upon cooling. The dried material was reconstituted to form a paste that exhibited gel-like properties upon standing, but that flowed readily when shear was applied. The rheological properties of these pastes were measured to determine the effects on the flow properties of the solids concentration in the reconstituted paste, the method of sample drying and reconstitution, and of fatty acid type. The materials were very spreadable and at the highest concentrations their flow properties were similar to a commercial shortening. The pasting properties of the dried solids were also examined.