Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2014
Publication Date: 10/8/2014
Citation: Felker, F.C., Fanta, G.F., Kenar, J.A. 2014. Starch nanoparticles formed by rapidly cooling dispersions of amylose-oleic acid complexes [abstract]. American Association of Cereal Chemists' International.
Technical Abstract: There is increasing interest in the preparation of starch-based nanoparticles for a variety of uses, such as biobased fillers in polymeric matrices to improve structural or barrier properties. Most established methods for preparing these nanoparticles involve acid hydrolysis of starch coupled with mechanical disruption. In this study, a method was developed in which nanoparticles were formed spontaneously by the precipitation of spherulites from amylose inclusion complexes formed from high amylose starch (12.5-100 g/L) and oleic acid (10% based on amylose content) when mixtures of these two components were passed through an excess steam jet cooker. Whereas previous work revealed that cooling such dispersions to room temperature over a two-hour period produced spherical particles about 1 µm in diameter, more rapid cooling, such as 10 min or 10 sec (collecting the jet-cooked dispersion directly onto crushed ice) gave particles ranging from 50-300 nm. The size of the nanoparticles was determined by scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. There was a tendency of the nanoparticles to aggregate, and although SEM revealed individual spherical particles, DLS data suggested that aggregates were also present. Nanoparticle yields were typically about 80% based on the starting starch weight. Identity of these particles as amylose-oleic acid complexes was confirmed by X-ray diffraction. Since this method for preparing starch-based nanoparticles requires only steam jet cooking followed by rapid cooling, it can be readily adaptable for large-scale processing.