Why does Pasta create foam when boiling?

http://en.wikipedia.org/wiki/pastaPasta is made from durum wheat, a particularly hard wheat. More precisely, pasta is created from durum wheat semolina, fine particles derived from the much coarser durum. The extraction of the semolina is largely responsible for the foaming of th pasta when cooking.
Durum wheat semolina consists of carbohydrates (starches) and protein. In the process of grinding wheat to extract semolina, some starch links are broken.
When pasta is put in boiling water, these starch links swell up, taking in tiny bubbles, along with water. These air bubbles come to the surface of the boiling water and appear as foam. So the foam is a combination of starch molecules, water, and air.