SC - Food dyes

[Decker, Terry D.]

This one got me wondering, so I took a few minutes to chase down a little
information.

The blue dye from indigo and woad is indigotin which is derived from the
glucoside indican.  The fermentation process to extract indigotin from woad
is described at:

http://www.botgard.ucla.edu/html/botanytextbooks/economicbotany/Isatis/

A home ammonia-extraction process is described at:

http://www.net-link.net/~rowan/crafts/woad/woadpage.html#Top

The chemical structure suggests that part of the extraction process from
indican to indigotin is nitrogen-fixing, so uric acid from urine might be a
workable substitute for ammonia, in much the same manner urine is used in
primative tanning processes.

Just for fun, here's a look at a medieval woad mill:

http://www.erfurt-guide.de/se2.htm

>From a few small references, it looks as though indigo began being used in
Europe toward the end of the 12th Century and gradual replaced woad.

I've found no reference to psychotropic properties.

Bear