Vegan's gelatin substitute (4)
I believe the answer is:
agar
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vegan's gelatin substitute</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for agar that I've seen before include "Substance derived from seaweed" , "found in the sea" , "Jelly medium" , "Food thickening agent obtained from seaweed" , "What comes out of seaweed" .)