Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2005
Publication Date: N/A
Technical Abstract: The structural components of citrus processing residues with significant functionality are the homogalacturonan regions of pectin. Functional properties of these regions include ion binding, propensity for gelation, water retention and the ability to elicit defense responses to pathogenic challenges. They are also sites of attack by commercial pectinolytic enzymes used as processing aids for viscosity reduction, enzymatic peeling and conversion of peel polysaccharides to monomeric sugars for subsequent fermentation. More recently endo-polygalacturonases have been used as a research tool to probe the mode of action of pectin methylesterases and to map pectin fine structure. A major limitation in studying the functionality of these oligomers has been the difficulty associated with their preparation, which was largely due to limitations on chromatographic detection. In this study, I report on the production and detection of narrow-range size-classes of polygalacturonic acid oligomers. Three size-classes with a degree of polymerization ranging from 1-8, 8-24 and 22-45 galacturonic acid residues were prepared by enzymatic digestion followed by a combination of differential pH and alcohol precipitation. These size-classes can now be used to probe the mode of action of endo polygalacturonase, to study their ability to elicit defense responses to pathogenic challenge and test their properties related to ion binding, gelation and water holding capacity.