Ratanda was a drink made from a nut that the Thals cultivated on Skaro. When it was boiled it produced a taste that was reportedly akin to orange juice.
When Ian Chesterson, Barbara Wright, Antodus, Elyon, Ganatus and Kristas crossed the Lake of Mutations, they brought Ratanda with them to drink. (PROSE: Doctor Who in an Exciting Adventure with the Daleks)