Processed grain etc, providing food (8)
I believe the answer is:
catering
'providing food' is the definition.
'processed grain etc' is the wordplay.
'processed' indicates an anagram.
'grain'+'etc'='grainetc'
'grainetc' anagrammed gives 'CATERING'.
(Other definitions for catering that I've seen before include "Providing food and drink" , "The supplying of meals" , "provision of food" , "essential feature of the tourist industry" , "Providing food, entertainment etc." .)