When coconuts mature, what will be the white flesh starts as a thin layer of clear jelly. The jelly gets thicker and more dense as the coconut gets older until the dense meat that we are after is all present, lining the shell.
While this is happening, the juice (milk) which is mostly water (from the ground via the tree's phloem cells) starts off a bit cloudy but clears and becomes sweeter (through photosynthesis)as the coconut matures.
The protective inner shell develops simultaneously as does the fibrous outer shell that we don't tend to see very often but is useful as a floor covering when woven.
- blakestyger - 19th Jul 08