Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 6, 2006
Publication Date: July 30, 2006
Citation: Fishman, M.L., Cooke, P.H., Chau, H.K., Coffin, D.R., Hotchkiss, A.T. 2006.Pectin: Networks, Clusters, and Molecules. In "Advances in Biopolymers: Molecules, Clusters, Networks and Interactions" M. L. Fishman, L. Wicker, and P. X. Qi (Eds.). ACS Symposiuim Series 935, American Chemical Society, Washington, DC, pp.201-214. Technical Abstract: Time dependent microwave assisted extractions of pectin from lime and orange albedo, have revealed that with increasing time of heating, molar mass and size decreased. In contrast, Mark-Houwink exponents, a measure of the rate of change of the molar volume with molar mass, increased with time. Based on these experiments it is hypothesized that pectin network structures gradually break down during the extraction process with increasing heating time. Initially networks degenerate to partially formed networks (clusters or branched structures) and finally to a mixture of linear molecules in the shape of rods, segmented rods and kinked rods. Additional evidence for this model was obtained from electron micrographs of pectin deposited on mica from solution which showed the presence of all the structures described above. Furthermore, pectin imaged in native sugar acid gels by atomic force also revealed that pectin existed in these gels as partially formed networks.