Beat broth mixture (5)
I believe the answer is:
throb
'beat' is the definition.
(throb is a kind of beat)
'broth mixture' is the wordplay.
'mixture' indicates an anagram.
'broth' with letters rearranged gives 'THROB'.
(Other definitions for throb that I've seen before include "Martin -; Kingsley -" , "Pulse" , "Vibrate with rhythm like heart" , "Pound" , "Drum" .)