Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
12.7 CONCLUDING REMARKS
From a physicochemical and materials perspective, pectin is potentially a very useful
macromolecule. Being a polyelectrolyte, its behavior is very sensitive to ionic effects;
also, its charge and its distribution along the pectin backbone can be varied in a
rather defined way through the use of chemical and enzymic methods. The sensitivity
of material properties to ionic environment is potentially important in its role as a
structural component of the plant cell wall. Simply by changing the ionic environment
of the apoplast it might be possible to induce large changes in material
properties of the cell wall. From a physicochemical point of view, this would seem
rather attractive compared with the requirement to export an enzyme into the plant
cell wall (which is a very dense network and not that porous to macromolecules) to
modify a covalent cross-link. The ability to alter charge distribution opens up the
possibility of using pectins more widely. For example, it is possible to envisage the
fabrication of pectin films that maintain their integrity under one set of environmental
conditions of pH and ionic strength yet swell markedly under another set of conditions.
Such devices may well find use for the encapsulation and then release of active
species.
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