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United States Department of Agriculture

Agricultural Research Service

Title: Fatty Acid Type Influences Morphology of Spherulites Formed from Jet-Cooked Fatty Acid/defatted Starch Mixtures

Authors
item Felker, Frederick
item Fanta, George
item Shogren, Randal
item Salch, John

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: September 14, 2005
Publication Date: September 14, 2005
Citation: Felker, F.C., Fanta, G.F., Shogren, R.L., Salch, J. 2005. Fatty acid type influences morphology of spherulites formed from jet-cooked fatty acid/defatted starch mixtures [abstract]. American Association of Cereal Chemists Meetings. Paper No. 145.

Technical Abstract: The formation of polymorphic spherulites during slow cooling of jet-cooked cornstarch dispersions has been previously described. Mixtures of large spherical/lobed and smaller torus/disc spherulites in various proportions are usually formed, depending on conditions. This study was undertaken to determine the mechanism of spherulite formation and to produce spherulites of a single morphology. Cornstarch was defatted to remove native lipids, and then jet-cooked in the presence of pure, specific types of fatty acids or their Na salts. Spherulite yields ranged from 8% to 28% based on starch. It was possible to produce nearly pure preparations of small torus/disc spherulites with palmitic acid. Linoleic and oleic acids yielded essentially pure large spherical/lobed spherulites. In some cases, the Na salts of the fatty acids yielded mixtures of spherulite types, but this was not seen with Na linoleate. Results were also influenced by pH and fatty acid concentration. The X-ray diffraction patterns of fractionated spherulites generally corresponded to their previously determined, characteristic patterns. However, some unexpected observations suggest that subtle differences in the composition, pH, and cooling rate may influence the growth of spherulites, and that their morphology is very sensitive to these or other factors.

Last Modified: 12/20/2014
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