What a surprise, mother sounding so savoury (5)

I believe the answer is:

umami

But I can't explain it at all!

(Other definitions for umami that I've seen before include "Savoury taste sensation produced by glutamates - I, a mum (anag)" , "Fifth flavour" , "meaty taste" , "Japanese word for pleasant savoury taste" , "Savoury flavour" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app