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' shows that the letters should be reversed in order.
'the juice' becomes 'sap' (juice from a plant).
'green' becomes 'sage' (shade of green).
'sap' backwards 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" .)