Pectic polysaccharides enzymic degradation

Cellulose and complex pectic polysaccharides are the main matrix of the water-insoluble residue after centrifugation of fruit and vegetable homogenates. The use of pectinolytic enzymes is therefore necessary to solubilize the solid sample. Pectinolysis is known to degrade efficiently large pectic polysaccharides, but some of them, for example, rhamnogalacturonan-II, are considered to be resistant to pectinolytic enzymes [45]. A mixture of commercial products Rapi-dase LIQ and Pectinex Ultra-SPL , was reported for the release of metal-complexes from the solid parts of edible plants, fmits, and vegetables [45]. 

The availability of these novel enzymes, next to the known pectic enzymes, offer new opportunities to use them as analytical tools in revealing the structure of oligo- and polysaccharides [31,32]. In contrast with frequently used chemical degradation methods, which usually have a poor selectivity, these enzymes act in a deflned way. To be able to recognize different structural units within the polymer, endo-acting types of enzyme are preferred, although accessory enzymes might be essential as well [30]. 

Water-soluble polysaccharide species with higher molecular weights can be readily degraded by enzymic hydrolysis with a mixture of pectinase and hemi-cellulase to release the dRG-II complex [45]. The same mixture was found to be efFcient to extract the dRG-II D metal complexes from water-insoluble residues of vegetables, owing to the destruction of the pectic structure [45]. 

More knowledge of physical and chemical properties of pectic enzymes, their substrate specificity, pattern of action, action on plant tissues, interaction with each other and other polysaccharide degrading enzymes is essential to establish their technological roles and to improve existing applications and to develop new applications. 

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