Preserve item, often mechanical, a source of drama (6)
I believe the answer is:
quince
'preserve' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for quince that I've seen before include "Golden fruit" , "Chips" , "Fruit - Shakespearian carpenter" , "Fruit for jelly" , "sliced fruit for newly-weds" .)