All you have to know about fruits and vegetables IV
An effect of maturation of vegetables is the thickening of the skin resulting in a decrease of tenderness. The turgor is responsible for the firmness, it is the pressure exerted by water on the membrane of cells of the vegetables. Over time, the vegetable loses moisture, wich reduces its firmness.
Some vegetables such as cucumber and tomatoes are treated with a water soluble wax to prevent moisture loss, which helps to keep a nice texture much longer. Vegetables that have lost their firmness are still safe for consumption and can easily be incorporated into soups or stews.