Glyoxal hardening

This relates back to the question of how-hard-is-hard-enough, from an
earlier discussion.

I found some glyoxal-hardened gelatin (.6% glyoxal in 3.5% gelatin)
dried in the bottom of a throwaway plastic container. I popped the thin
disk of hardened gelatin out by flexing the container. In its amber
color, transparency, and hardness this disk was very similar to a disk
of dried unhardened gum. And, just like dried gum, it made a hard sound
like hard plastic when snapped with a fingernail.

But when I poured boiling water on it, it crumpled and then melted.
There are many different possible criteria for whether gelatin is
hardened "enough" or not, but if the criterion is that it will withstand
boiling water, this .6% glyoxal doesn't seem to cut it.
Katharine Thayer
Received on Wed May 4 16:48:32 2005