Ziziphus species?- Singapore market

https://08511630493324166816.googlegroups.com/attach/8d82e7f660acfe80/ASP10.JPG?part=0.1&view=1&vt=ANaJVrHb9vBe22YM_JU1nwmET9VYFEHuT25Bhpjr2e1KZ5NnlzUaISjZ8Ths_O0lM7Dd7HZeLDiL9lBaLf93RuOnkXDnpwwNEWwUDvHiJ6lvudYk7IhLlNc
Plant ID 100513ASP10 : Attachments (1).  2 posts by 2 authors.
This fruit was taken in a Singapore market in October 2012. It is said to be edible, eaten raw, cooked or pickled.
Details of the tree is not known.
Can you please ID this

Zyziphus ??

I think this is Manilkara zapota (sapodilla)

Seems too small for Manilkara zapota

Also looks dry, Zizyphus seems likely choice.