This feature of the game is currently Unreleased. There may be changes in the future that will affect the development of certain features of the game.
Kookadoba Fruit is a food that is intended to be released for 1.1.0 as a part of Ogden's Wild Update. They are an upcoming feature.
Take a side job working for Ogden Ortiz and explore the Wilds, an untamed island on the Far, Far Range full of primitive, feral slimes! Ogden will offer you unique rewards for collecting the rare kookadoba fruit that grows in the Wilds.