From the Super Mario Wiki
Artwork of a Papaya

A Papaya is a kind of fruit found in Isle Delfino, and on Earth in the tropical regions of the Americas. It appears in the game Super Mario Sunshine. If a Yoshi eats a Papaya, it becomes orange and can spit Juice of the same color, which turns enemies into orange stationary platforms.

In the Super Mario World episode King Scoopa Koopa, papaya fries were served at Koopa's fast food stand.