Why does salt absorb water from eggplants?

Eggplants do not absorb water when exposed to salt. Instead, salt draws moisture out of the eggplant in a process called osmosis. Osmosis is the movement of water molecules from a region of high water concentration (inside the eggplant) to an area of low water concentration (the salt). Adding salt to the surface of an eggplant causes water to move from inside the vegetable to the surface where the salt is. The water then evaporates, leaving the eggplant drier.