The Collaborative International Dictionary of English v.0.48:

Gelatinate \Ge*lat"i*nate\, v. t. [imp. & p. p. Gelatinated;
   p. pr. & vb. n. Gelatinating.]
   To convert into gelatin, or into a substance resembling
   jelly.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gelatinate \Ge*lat"i*nate\, v. i.
   To be converted into gelatin, or into a substance like jelly.
   [1913 Webster]

         Lapis lazuli, if calcined, does not effervesce, but
         gelatinates with the mineral acids.      --Kirwan.
   [1913 Webster]