BACKGROUND: Watermelon (Citrulluslonatus(Thunb.) Matsum&Nakai) fruit matrix glycans are comprised largely of xyloglucans (XGs). As in other fruits, these polymers show significant molecular mass downshifts during ripening. In the present study, we describe the purification and characteristics of a number of xyloglucanases (XGases) from the placental tissue of ripe watermelon. XGases were extracted from watermelon fruit placental tissue and purified by sequential ion-exchange, gel-permeation and concanavalin A chromatography.