Pectin-degrading enzymes, applications

Pectin as one of the major plant cell wall constituents has received much attention both from a scientific and a technological point of view. Although pectin has been known to be a very complex heteropolysaccharide for quite some time, most progress on the elucidation of its structure has been attained in the last decade as a result of refinement and development of new more powerful techniques like HPAEC, HPGPC, NMR and the application of purified enzymes able to degrade specific parts of the complex molecule. 

Further research is directed to the determination of the fine-structure of the pectins and hemicelluloses isolated from soy meal, using chromatography and degradation with specific enzymes. With these results a model of the polysaccharides present in the cell wall of soy will be formulated. Furthermore, application directed experiments will be performed to obtain information about structure-function relationships. 

Pectinases These enzymes carry out the hydrolytic degradation of the D-glycosidic linkage in pectins. The latter substances, also known as pectic substances, are polymeric components of plant cell walls and. like starch, are composed of sugar residues linked by glycosidic bonds. The chemistry is the same as that shown for the amylases previously described. The main application of pectinases is in the production of fruit juices, wines, and certain other food products. 

Other commercial applications are found in the food industry, where lyases already have a long history of safe use. In these applications, isolated enzymes are preferred for safety reasons. Well-known examples include lyases that degrade polysaccharides, such as pectin (pectin lyases), alginate (alginate... 

Pre-fermentation processing enzymes have been used for a long time by the wine and juice industries (van Rensburg and Pretorius, 2000). The first commercial enzyme preparations used were pectinases, enzymes responsible for the breakdown of pectin. Conventional application of pectinases pre-fermentation can enhance juice yield by degrading polysaccharides (e.g., pectin) that interfere with juice extraction. These preparations also improve the extraction of color (red wines) and flavor molecules trapped in grape skins as well as reduce the potential for post-fermentation instabilities. Newer commercial preparations may also contain secondary activities such as the ability to degrade cellulose to further enhance cell wall breakdown. 

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