The Collaborative International Dictionary of English v.0.48:

Levulin \Lev"u*lin\ (l[e^]v"[-u]*l[i^]n), n. (Chem.)
   A substance resembling dextrin, obtained from the bulbs of
   the dahlia, the artichoke, and other sources, as a colorless,
   spongy, amorphous material. It is so called because by
   decomposition it yields levulose. [Written also
   l[ae]vulin.]
   [1913 Webster]