Adding new properties to org-global-properties variable doesn't work

Question

I am trying to add a multi value property globally to make auto completion available while adding Project property to headings.

  (setq org-global-properties '(("Project_ALL" . '("business" "professional" "personal"))))

When I check the value of this variable, it is set. But while setting a property to org-set-property, property Project does not appear in the auto complete drop down.

Note: I am using prelude emacs.