The pineapple juice on the crust was something I picked up from the parlour I used to work at.
They used to keep the pineapple juice from the canned pineapple which was put on as toppings. They would put the juice into the prep table and use it to "lubricate" their hands while applying their raw meats. If you take a chunk of raw sausage, dip it in pineapple juice, your hands don't really stick to it all that much.
Seeing how this gave the pizza a sweeter taste, I suggested to them that they actually rub a little on the actual crust of their more "signature pies". The glazed taste of the crust was fantastic!