In a bowl, whisk together the pineapple juice, melted butter, sugar and eggs. Set aside.
In a stand mixer using the dough hook, or in another bowl using a wooden spoon, combine the flour, yeast and salt. Add the juice mixture and knead until the dough begins to form.
In the stand mixer or on a lightly floured surface, knead the dough for 5 minutes. It will be soft and slightly sticky. Place in a lightly oiled bowl and cover with a damp cloth or plastic wrap. Let rise in a warm, humid place for 1 hour and 30 minutes or until it has doubled in volume.
Butter a rectangular 13 x 9-inch (33 x 23 cm) baking dish.
Divide the dough into 15 pieces. On a lightly floured surface, roll the dough into balls using the palm of your hand. Place the balls into the prepared pan and cover with a damp cloth or plastic wrap. Let rise for 1 hour and 30 minutes in a warm, humid place until the dough has doubled in volume.
With the rack in the middle position, preheat the oven to 375°F (190°C).
In a small bowl, lightly beat the egg yolk and water. Brush on the dough, if desired.
Bake for 13 to 15 minutes or until the rolls are golden brown. Let cool.