I know this:you cannot make decent gazpacho with the fresh tomatoes sold in the US. If you put Spanish tomatoes in a blender, the puree is RED and tastes like tomatoes. US tomatoes come out pink and taste more or less like cardboard. Gumbo comes out tasting great with canned stewed tomatoes: with fresh tomatoes, there is no tomato taste.
There is nothing on the label that indicates any wheat product: usually onion powder, sugar and salt.
Italian canned tomato paste seems to be best, though US canned tomatoes are also acceptable.