By "associated" I mean "named after it". This is clear by context given OP is asking about "veggie-fructose" and "vructose", as if you got some substance out there named after vegs.
And yes, as my answer shows it, I am aware vegetables often contain fructose.

It's more complicated than that — there are two partially overlapping bundles of meaning associated with the word "fruit":
Those bundles of meaning could be associated with different words*, but in English they happen to be associated with the same word.
So. Tomatoes, bell peppers, cucumbers etc. are botanical fruits (sense #1), but they are not culinary fruits (sense #2). With strawberries and rhubarbs being kind of the opposite: culinary-wise they're treated as fruits, but one is a receptacle and the other a petiole (leaf stem).
*Portuguese splits both into "fruto" and "fruta" respectively.