I'm not a native speaker of Portuguese but this is what I know. Da means give or to allow and de means of. In this context, you are stating that the girl drinks orange juice which is "suco de laranja" not "suco da laranja" which translates to juice orange. Like if you were to say carrot cake, you would put "bolo de cenoura". This is like saying "a cake of carrot" just like "suco de laranja" means "juice of orange". I hope this helped.