Polygalacturonase has the same substrate specificity as pectate lyase. This enzyme is produced by Erwinia carotovora subspp. but not by Erwinia chyrsanthemi.
See, applesauce is full of a polysaccharide called pectin, which normally holds cell walls together in some plants, including fruits like apples and berries.
One ingredient that can help keep the water from escaping is something that occurs naturally in the fruit itself: a carbohydrate called pectin, which normally helps hold cell walls together.
Wax currants are not a popular berries since they barely have any flavor, but they have very high pectin content and so it's quite easy to mix them with another berry and make jams or jellies and preserves.