Call on eg stews for protein (8)
I believe the answer is:
collagen
'protein' is the definition.
(collagen is a kind of protein)
'call on eg stews' is the wordplay.
'stews' indicates an anagram.
'call'+'on'+'eg'='calloneg'
'calloneg' with letters rearranged gives 'COLLAGEN'.
'for' is the link.
(Other definitions for collagen that I've seen before include "Fibrous protein in connective tissue" , "Animal tissue protein" , "Tough fibrous protein, in skin say" .)