I don’t know a lot about it, but here is the wiki page for guar gum:

http://en.wikipedia.org/wiki/Guar_gum

It is used as a thickening agent because only a little bit is needed to achieve a good thickness. So, it’s sort of like cornstarch, but more powerful. It’s from a plant and doesn’t seem to be highly processed– the seeds from the guar bean plant are dehusked and milled to make the gum. Hopefully the article above will provide you with more information.

I bet you could achieve the same soft serve consistency by blending a young coconut (the meat with the water), combining that with some vanilla bean and then freezing it. Once it’s semi-frozen, you could blend it again, like how many raw “ice creams” are made. A great raw cookbook is the one from Cafe Gratitude in SF. They do all sorts of amazing things with coconut, even making a raw, cultured yogurt out of it (although I’m not completely sure that recipe is in the book). The food at Cafe Gratitude is amazing and so is the book! I highly recommend.