I knew that the cigarette industry squeezed the juices to re-case their tobaccos with exact tars and nicotine doses, but I have never pressed tobaccos. I don't think I've ever rehydrated my tobaccos with enough liquids to make a juice if pressed.
I've tasted a prune-ish flavor in pure tobacco before, but I think that a lot of companies add sugars in the casing which may hasten this flavor. I've always thought that the weird flavor in Royal Yacht was from an artificial prune flavoring that may have been added to make RY taste more like a real VaPer in the beginning, but somewhere over the years the formula fell out of synch with the tobaccos that were available to make RY, and we were left with that weird flavoring in Royal Yacht.