Choose plantains with uniform shapes. Avoid those with bruises or gouges. Plantains are often sold in their hard, green stage. Like bananas, the skin of the plantain will first turn yellow and then darken as the fruit ripens. Plantains with dark skins indicate ripe, sweet fruit that is ideal for use in a cooked dessert. Black-skinned fruit with mold around the stem end indicates old product and should be avoided.