Eggs,
chicken and
pork all benefit from not being
overcooked. Overcooked
scrambled eggs will be watery. Why? Well, when the eggs first
set, they've reached a temperature of about 145°F. They are ready to eat at this point. If the
temperature of the eggs rises further, to about 165°F, the
protein in the eggs undergoes a second
chemical change which results in a tighter protein matrix. This
squeezes
water out of the eggs, resulting in
tough watery eggs.
A similar process occurs in pork. When pork is just done, it's at about 145°F as well. It is as tender as it will ever be. If the temperature of the pork is allowed to rise over about 170°F, water will be squeezed out of the pork, and the pork will toughen. Unlike the ruined eggs, however, the pork can be brought back to salvation. Heating to 185°F for an extended period of time results in a third chemical change in the pork. This change affects the interconnectedness of the individual strands of muscle constituting the pork. The pork will break into pieces after heating this hot over a long period of time. This is the fundamental goodness of Carolina Bar-B-Que.
Chicken breast behaves much like pork in that it possesses a similar set of three chemical changes that occur as it's cooked, at similar temperatures. Another aspect of cooking to the second degree of tender is that a smaller piece of meat is produced. Some pork will shrink by as much as 50% during good pulled pork cooking.