I would like to know if it's possible to install Scratch text-editor in Ubuntu 16.04.
You might want try to compile it under Ubuntu with static linking so that granite and other libraries does not interfere with your default Ubuntu desktop experience. Source is available at https://launchpad.net/scratch as Pretzel Jones pointed out in his answer.
I don't know, this is an elementary forum, not Ubuntu. j/k! I'm sure you could build it from source (https://launchpad.net/scratch) but it's really just a fork of Gedit. You can find that in the repositories in Ubuntu and it should work just as well for you. Besides Scratch might look funny in Unity due to it's client-side decorations.