Edible starch (4)
I believe the answer is:
sago
'edible starch' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sago that I've seen before include "Starchy pudding cereal" , "Cereal, used in pudding" , "Powdery starch used in cooking" , "Powdery starch from a palm" , "Edible powdery starch" .)