> My recollection is that arrowroot powder is starch
> extracted from the root. Is it simply a process of
> running water through the chopped root and collecting
> the starch, or is there more to it?
> 
> Andrea
> 

Arrowroot powder is starch processed from tubers native to the New World. I
don't know why some consider it Paleo, unless they consider starchy tubers
Paleo (which Ray Audette and Loren Cordain do not). I searched but did not
find a good explanation of this. Perhaps it's seen as a compromise, less-bad
than grains (which it likely is). 

There is a claim here
http://www.herbsarespecial.com.au/free-herb-information/arrowroot.html that
arrowroot can be eaten raw, but being able to eat something raw doesn't
guarantee it's Paleo or biologically appropriate. My grandfather ate white
potatoes raw and I've eaten green beans from the garden raw, but those
aren't considered Paleo or biologically appropriate. 

People I know who have switched to Paleo or near-Paleo tend to have trouble
giving up gravies and thickeners and don't like the Paleo thickener
suggestions I have seen here and at Paleofood.com (such as using nut meal or
pureed onions), so they end up using arrowroot or rice flour.