Jelly, pavlova, gargantuan wraps (4)
I believe the answer is:
agar
'jelly' is the definition.
(gelatinous substance)
'pavlova gargantuan wraps' is the wordplay.
'wraps' indicates a hidden word (wrap can mean cover or conceal).
'AGAR' can be found hidden inside 'pavlova gargantuan'.
(Other definitions for agar that I've seen before include "Food thickener (derived from seaweed)" , "contribution to culture?" , "Jelly medium" , "that aids culture" , "part of culture?" .)