Unlike many vegetables, eggplant is not harmed by long cooking. An undercooked eggplant can have a chewy texture; but overcooked eggplant is just very soft. Do not cook in an aluminum pot because the eggplant will become discolored.
How do I know when eggplant is done?
Eggplants should be picked as soon as they are ripe, with slightly immature fruits tasting best. One of the easiest ways to determine if they are ripe is to gently squeeze the eggplant. Once you release, the skins should bounce back. If indentations remain, the fruit is not quite ripe yet.
Is it OK to eat eggplant that is a little brown inside?
Eggplant flesh will have tan to brown colored spots around the seeds. If this is the color you are referring to, it is edible. If the flesh is more brown than white, the eggplant may be spoiling and should be discarded.