Baking ingredient in vegan line manufactured (9)
I believe the answer is:
leavening
'baking ingredient' is the definition.
(substance used to make dough rise)
'vegan line manufactured' is the wordplay.
'manufactured' is an anagram indicator.
'vegan'+'line'='veganline'
'veganline' is an anagram of 'LEAVENING'.
'in' acts as a link.
(Other definitions for leavening that I've seen before include "eg Yeast" , "Riser" , "Influential agent" , "Pervading, causing gradual change" , "instigator of rising" .)