VEGETABLE COOKING
When we cook vegetables, the green color molecules leak out into the water at temperatures around 70 C/160 F. Of course, we do like to have veggies that retain as much of their color as possible, so the only way to cook them is to make them pass through this temperature range as quickly as possible, in both directions. In practice then, we put the green veggies in boiling water (quick heat transfer up) and when they are just about to be cooked through, we remove them from the heat and put into iced water for a brief time (quick heat depletion down).