I suspect the OP has confused what is meant by a pure substance and pure orange juice. The phrase pure substance generally refers to a substance that is chemicaly pure. It is composed of a only one type of molecule or atom. So pure water contains only H2O, pure gold only contains gold atoms etc. read more
Orange juice is not a pure substance but a mixture of different pure substances. Pure substances are made of only one type or atom or molecule. Orange juice, even fresh squeezed from the orange and not reconstituted with water and concentrate, is made of of multiple different substances, including sugar, citric acid, vitamin C and water. read more