Identification of complexed native lipids in crystalline aggregates formed from jet cooked cornstarch

Crystalline aggregates, resulting from crystallization of helical inclusion complexes of amylose with the native lipids in jet cooked cornstarch, exhibit two distinct morphologies: smaller, torus-shaped and larger, spherical/lobed particles. Gas chromatographic analyses of extracted lipids showed that these two species contained mixtures of the same native lipids found in granular cornstarch, although in different relative amounts; especially the 16:0 (palmitic) and 18:2 (linoleic) components. The torus-shaped particles contained about twice as much palmitic as linoleic acid; whereas these ratios were reversed in the lipids extracted from the spherical/lobed particles. These findings are consistent with X-ray diffraction data. Microscopic examination of crystalline aggregates formed at different temperatures showed that the spherical/lobed particles are the first to form, and that the torus-shaped particles form at a lower temperature. The fact that the composition of the lipid mixture extracted from the spherical/lobed particles closely resembles that of the lipid mixture extracted from cornstarch itself is consistent with the fact that these particles are the first to form.