What white substance comes from yam?

The white substance that comes from yam is called yam flour. Yam flour is a fine, powdery substance that is made from dried and ground yams. It is used as a thickening agent in soups, stews, and other dishes. It can also be used as a flour to make bread, cakes, and other pastries. Yam flour is a good source of dietary fiber, vitamins, and minerals.