The Collaborative International Dictionary of English v.0.48:

Gelatinize \Ge*lat"i*nize\, v. t.
   1. To convert into gelatin or jelly. Same as Gelatinate, v.
      t.
      [1913 Webster]

   2. (Photog.) To coat, or otherwise treat, with gelatin.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gelatinize \Ge*lat"i*nize\, v. i.
   Same as Gelatinate, v. i.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gelatinize
    v 1: coat with gelatin
    2: become gelatinous or change into a jelly; "the starch
       gelatinized when it was heated" [syn: gelatinize,
       gelatinise]
    3: convert into gelatinous form or jelly; "hot water will
       gelatinize starch" [syn: gelatinize, gelatinise]