Onychopetalum periquino "Mini Amarela / Small Yellow", commonly known as Envira Caju in Brazil. A member of the annonaceae family. The fruit is mostly juicy yellow pulp by weight. The pulp is a bit astringent near the endocarp, the mesocarp is much less astringent, and the skin is fairly thin.
Learn more here: http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:985076-1