Like a producer of egg white (5)
I believe the answer is:
ashen
'white' is the definition.
(I know that white can be written as ashen)
'like a producer of egg' is the wordplay.
'like' becomes 'as'.
'a producer of egg' becomes 'hen' (I can't justify this - if you can you should give a lot more credence to this answer).
'as'+'hen'='ASHEN'
Can you help me to learn more?
(Other definitions for ashen that I've seen before include "Pale of face, quite grey" , "White" , "pasty" , "(Of face) pale with fear" , "Shane (anag.)" .)