Bitter and sour, say, from Left cutting benefits (8)
I believe the answer is:
flavours
'bitter and sour say' is the definition.
(bitter and sour are flavours)
'left cutting benefits' is the wordplay.
'left' becomes 'l' (common abbreviation).
'cutting' is an insertion indicator (some letters cut their way into a word).
'benefits' becomes 'favours' (favour can mean to benefit).
'l' put within 'favours' is 'FLAVOURS'.
'from' acts as a link.
(Other definitions for flavours that I've seen before include "Tastes" , "Taste experiences" , "Sensations perceived when eating or drinking" .)