On Food and Cooking: The Science and Lore of the Kitchen

Proteins unwind when exposed to heat, and they do the same when exposed to salt. So salting has an effect resembling cooking.

Overcooking traps these flavorful materials in an indigestible matrix of polymerized flesh that forms when meat begins to dry out. You can only taste, and your body can only make use of, minerals that remain free and available.