Structure and functionality of surface-active amylose-fatty amine salt inclusion complexes

Authors: Selling, Gordon; Hay, William; Peterson, Steven - Steve; Hojilla-Evangelista, Milagros - Mila; Kenar, James - Jim; Utt, Kelly

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2024
Publication Date: 4/21/2024
Citation: Selling, G.W., Hay, W.T., Peterson, S.C., Hojilla-Evangelista, M.P., Kenar, J.A., Utt, K.D. 2024. Structure and functionality of surface-active amylose-fatty amine salt inclusion complexes. Carbohydrate Polymers. https://doi.org/10.1016/j.carbpol.2024.122186.
DOI: https://doi.org/10.1016/j.carbpol.2024.122186

Interpretive Summary: Emulsifiers are materials needed in nearly all industries. These compounds allow otherwise incompatible materials, such as oil and water, to mix together without separation. Commercially available starch emulsifiers require modification with regulated chemicals. ARS scientists in Peoria IL developed new types of low-cost starch emulsifiers that do not require chemical modification to function. The emulsifiers, called amylose inclusion complexes, or AIC, are made by heating starch and fatty amine salts at high temperature and pressures. When the mixture cools the AIC forms, creating a new structure in the starch with emulsifying properties. There are no new chemical bonds in the AIC, it is a novel physical mixture. The ARS scientists studied the physical properties, structure, stability, and performance of these new compounds. They discovered that the AIC emulsifiers outperformed the standard commercial chemically modified starch emulsifier. The properties of these AIC can be adapted easily to fit the requirements of industrial producers. The new emulsifiers can be readily produced using common industrial production techniques. This technology will be useful to all participants in the starch value chain, especially corn producers. These AIC will provide industry and the ultimate consumer with new biobased emulsifiers that have unique value to produce improved products.

Technical Abstract: Starch-based emulsifiers are widely used in industrial and food processes. Herein, we evaluated and characterized amylose inclusion complexes (AIC) composed of fatty amine salts (10-18 carbons) and high amylose corn starch (HAC). The AIC, without new chemical bonds, were found to be highly effective emulsifying agents and their structural, rheological and emulsification properties were characterized. It was determined that a ligand required at least 14 carbon atoms to form a stable complex. The XRD and FT-IR spectra of the C12-C18 AIC confirmed complex formation and as the number of carbons in the ligand increased, the melting/freezing temperatures increased linearly. The presence of the fatty amine ligand increased the rate of thermal degradation. The surface tension of the AIC solutions ranged from 24 to 41 mN/m and displayed good surface active properties, competitive or superior to current starch-based offerings. The particle size of the AIC in solution were typically in the 100 nm range. The zeta potential of the AIC were generally low, except for the AIC containing excess ligand. The effect of time, temperature, pH and presence of ions on particle size was also determined.