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United States Department of Agriculture

Agricultural Research Service

Title: Calcium-Induced Supramolecular Structures in the Calcium Caseinate System

Authors
item QI, PHOEBE
item TOMASULA, PEGGY

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 11, 2007
Publication Date: August 18, 2007
Citation: Qi, P.X., Tomasula, P.M. 2007. Calcium-induced supramolecular structures in the calcium caseinate system. (abstract). American Chemical Society Book of Abstracts. AGFD14.

Technical Abstract: The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supramolecular structures in the calcium caseinate system by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). To further assess the intermolecular interactions that dominate and maintain these structures, the effect of ionic strength on the size distribution of these supramolecular structures was investigated in detail. The results showed that the size of these supramolecular structures reduced by nearly half as ionic strength increased from 0 to 0.3 M. AFM provided information on the basic sub-structures in the formation of these supramolecular structures on the nano-scale and suggested that a delicate balance between hydrophobic interactions and electrostatic interactions may be essential for the formation and stabilization of the self-assembled supramolecular structures. The effects of common biological buffers, imidazole, Bis-Tris and PIPES often used in Electron Microscopic imaging were also explored. It has been demonstrated that the choice of buffer in SEM imaging of the supramolecular structures in the calcium caseinate bears a significant influence on the size and distribution of these structures as well.

Last Modified: 7/25/2014