Webster's Revised Unabridged Dictionary · 1913

Gelatinate

Gelatinate , transitive verb

To convert into gelatin, or into a substance resembling jelly.

Gelatinate , intransitive verb

To be converted into gelatin, or into a substance like jelly.
Lapis lazuli, if calcined, does not effervesce, but gelatinates with the mineral acids. — Kirwan