Why does meat get tougher after cooking, but tender after cooking for a very long time (or under pressure)?

Question

Why does meat get tougher after cooking, but tender after cooking for a very long time (or under pressure)?

In: Biology

Answer 1

Not sure this is 100 percent correct, but my mom is a chef and said cooking a meat quickly with high temperature causes the moisture inside to evaporate which toughens the meat, but if done gradually ( depends on the meat ) with a correct temperature allows most of the moisture to stay, pressure cookers don’t allow the moisture to evaporate either I think.