Harmala Solution Changing Color

[josboaz]

Hi there,

So I did an alcohol extraction of Harmala seeds, I used 92% ABV Ethanol.
The red solution was filtered and I added water to it before cooking it, after all the alcohol was evaporated the liquid turned brown. I suspected that the alcohol would have extracted a different spectrum of the Harmala seeds. But the fact that the solution turned from red to brown upon changing the liquid content of alcohol to water. Got me thinking there is something else that plays a role. Does anybody have an explanation for this phenomenon?

 

[downwardsfromzero]

Simmer a simple strained (like tea, or a coffee percolator) brew for a little while and it goes from yellow, through orange to brown. Simmer it longer and it gets darker, and at some point some of the brown matter congeals to a fine powder. Both the heat and the oxygen from the air contribute to changes in the colour-bearing molecules. It's not especially to do with the change of solvent.

When I've let the fresh, yellow brew sit and dry out somewhat on a white porcelain surface, gently wiping off the yellow-brown residue has often revealed a red stain. Oxygen has turned some part of the harmala material red. There are some compounds present which air fairly oxygen-sensitive when in solution.

 

[Jees]

...In 1928 Syrian Rue was first planted in North America by a farmer who wanted to extract a red dye from it called 'Turkish Red'. By the way, this is still a way of coloring that is used...