"Quality protein" in my book is protein where the essential amino acids are roughly balanced in proportion to what a human body needs. The old standby, Diet for a Small Planet, contains plenty of information about food combining to make complete proteins.
I just read in the last couple of weeks that contrary to what dietitians have thought, complementary proteins do not need to be consumed in the same meal, although obviously it's convenient to do so.
(How come a serving of lentils is double the amount of a serving of black beans?)
Speed comes from what you put behind you. - Judi Ketteler