Source of a purple purée
I believe the answer is:
acai
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">source of a purple puree</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 acai that I've seen before include "something nutritional to eat" , "fruit which is nutritious" , "South American food product" , "South American palm tree" .)