The extract has turned the juice green (7)
I believe the answer is:
passage
'the extract' is the definition.
(I have seen 'Literary extract' mean 'passage' so perhaps 'extract' could also mean 'passage')
'turned the juice green' is the wordplay.
'turned' says the letters should be written in reverse.
'the juice' becomes 'sap' (I've seen this before).
'green' becomes 'sage' (sage green is a kind of green**).
'sap' in reverse letter order is 'pas'.
'pas'+'sage'='PASSAGE'
'has' is the link.
(Other definitions for passage that I've seen before include "Alley - corridor" , "Sea/air journey" , "street" , "Section of musical or literary work" , "Excerpt" .)