Alien Fruit — Harris Tobias

Alien Fruit is the first book in the YA sci-fi series, The Newark Trilogy. It is the story of a teenage couple living in a failing colony on Newark -- a planet whose biota can barely sustain them. The only native food that can sustain human life is the bland, barely palatable nukka. To complicate matters, the colony has split into feuding factions, those who trust the autocratic ship's captain and those who don't. Amidst this troubled backdrop our protagonists strike out into the unknown to find the rumored, legendary fruit that will revive the colony's fortunes. They have many narrow escapes and adventures along the way.