De or het glutenvrij?

The correct Dutch article is:

de glutenvrij

Rule Words ending in -ij and -erij: usually de. See the rule

How to use glutenvrij

the glutenvrijde glutenvrij
this glutenvrijdeze glutenvrij
that glutenvrijdie glutenvrij
our glutenvrijonze glutenvrij
your glutenvrijjouw glutenvrij
every glutenvrijelke glutenvrij
which glutenvrij?welke glutenvrij?
a big glutenvrij / the big glutenvrijeen grote glutenvrij, de grote glutenvrij