Yep, I know they use it in Pedigree and Wagg as well as many others.

It is a by-product of manufacturing sugar from beets. It is a controversial ingredient in dog food because it slows down the transition of rancid animal fats which causes stress to the kidneys and liver. Beet pulp is also linked to problems such as allergies, eye and ear infections. It is a form of fibre though.