Enzymes contained in many flowering plants which slowly split highly polymerised pectins into low molecular pectins and thus contribute to the softening of fruits. The soluble pectins get into the grape must during pressing and increase the viscosity (thick liquid) by binding effects, which may result, among others, in a lower juice yield. Normally, the grape's own pectinases are present in such quantities that the pectins are largely broken down during the maceration of red grapes or during the maceration of white grapes. However, the effect is inactivated by heat, for example. If necessary, pectolytic enzymes are added to the mash, but also to the must or young wine as a replacement or for the purpose of intensification. They are also known as oenological pectinases or antigel (antifungal agent).
Anti-gelling agents are obtained from mould and bacteria cultures. Frequently used are pectin lyases (PL), pectin methyl esterases (PME) and polygalacturonases (PG) which are approved within the EU. These cause a better release of berry juice and thus a better juice yield, as well as of colouring agents and extracts. In addition, they also facilitate the degumming of the must, cause a quieter fermentation with less foam formation, and support the clarification and filtration of the young wine. Glucanases partly have a similar effect, whereby both belong to the so-called oenological enzymes. See also under agents in vinification and a complete list of all wine ingredients under total extract.