Pectinase is a group of enzymes that break down a central part of plant cell walls. Enzymes are proteins that speed up the rate of reaction. These enzymes are an ubiquitous part of the fruit juice and wine-making industries. Also known as pectic enzymes, they are added to livestock feed to help animals better digest their feed. They are also sold as nutritional supplements for humans to aid digestion.
Different types of pectic enzymes vary in how they degrade pectin, a long polysaccharide of sugars that forms a gel. Pectin forms the center of the plant cell wall. Other molecules, like cellulose, are embedded in it. When pectin is degraded by pectinase, the cell walls become weaker. For instance, during fruit ripening, the enzyme polygalacturonase helps certain fruit, such as tomatoes, become soft and edible.
In other cases, fungi and bacteria produce these enzymes to break down cell walls as part of their invasion of plant tissue. This breakdown can cause total degradation of the tissue, such as when a potato gets soft rot. Pectic enzymes also help in the decomposition of plant litter, and are used in waste water treatment. Genetically-altered fungi are a major source of these enzymes for industry.
Commercially, pectinase is added to livestock feed to help the animals better digest their food. This improves the health of their digestive systems and helps them to better digest nutrients. It also allows them to be fed food that has not been processed too much, and costs less. Supplements containing enzymes that degrade plant materials are sold to help aid human digestion as well, although such supplements are not regulated by the United States Food and Drug Administration (FDA), so their efficacy is unclear.
The food and wine-making industries frequently use these enzymes in combination with amylase, which degrades starch, to clarify solutions. This is particularly true for apple juice, which is often cloudy due to plant materials that remain in it after production. Treatment with pectic enzymes degrades the pectin, helping to produce a clear juice. In making berry-based juices, such treatment can also improve the retention of aroma and coloring. A similar approach is taken with wine, which retains pectin.
Pectinase is also used when fruit is turned into pulp and then extracted to remove its juice because it has been found to improve the yield. Other uses for pectic enzymes in the food industry include softening fruit rinds to making peeling them easier, and to ferment coffee and tea. These enzymes are also used, along with other cell wall degrading enzymes, in the isolation of plant fibers, such as cotton, and reduce the need for toxic chemicals in such processes.