May 19/The Irish Times -- Glucomannan is a form of dietary fiber that has some properties similar to starch. It is obtained from the corms of a plant called konjac. A corm is an underground stem that is sometimes mistaken for a bulb, but instead of having moist layers, it is solid and hard like a potato.
Konjac is grown in Asia and used to make konjac flour and a vegan form of gelatine.