De or het eiwitmengsel?

The correct Dutch article is:

het eiwitmengsel

Rule Words ending in -sel: usually het. See the rule

How to use eiwitmengsel

the eiwitmengselhet eiwitmengsel
this eiwitmengseldit eiwitmengsel
that eiwitmengseldat eiwitmengsel
our eiwitmengselons eiwitmengsel
your eiwitmengseljouw eiwitmengsel
every eiwitmengselelk eiwitmengsel
which eiwitmengsel?welk eiwitmengsel?
a big eiwitmengsel / the big eiwitmengseleen groot eiwitmengsel, het grote eiwitmengsel