Older relative eats last of pitta bread (4)
I believe the answer is:
naan
'bread' is the definition.
(I know that naan is a type of bread)
'older relative eats last of pitta' is the wordplay.
'older relative' becomes 'nan' (informal term for grandmother).
'eats' is an insertion indicator.
'last of' suggests the final letters.
The last letter of 'pitta' is 'a'.
'nan' enclosing 'a' is 'NAAN'.
(Other definitions for naan that I've seen before include "Indian leavened bread" , "Indian bread shaped like a teardrop" , "Indian flat bread" , "foreign food" , "Slightly leavened bread" .)