Re: HYB: Abbey Road pigments (was on photos)

The pigment left in the alcohol is probably part of the water soluble yellow that didn't get extracted the first time, rather then a third pigment. There are water soluble and oil soluble pigments and they both disolve in alcohol ( except for lycopene). 
Some pigments are unstable and will deteriorate after a few days (or even hours eg anthocyanin in alcohol that is not acidified)

I had problems with emulsions until I started using combination of clear lamp oil, which is a light oil, and methyal hydrate which is a strong alcohol  (solvent) and with the two I get good seperations. Old flowers will produce some emulsions in best senarios.

I would still suspect the oil pigment is not a carotene , based on 1) carotene is usually darker in the flower and a bit greener in this light of a tone
2) we already have some flavanoid(assumption) or a water based pigment so amount of  carotene contributing to colour would be minimal and would not likely be so even a distribution
3) The colour of standards looks very smooth, delicate and  even in tone and in this shadding in more like an xanthophyll, a biproduct of carotene.

Chuck Chapman

Date: Sat, 14 May 2005 06:46:50 -0400
From: Linda Mann <lmann@volfirst.net>
Subject: [iris] Re: HYB: Abbey Road pigments (was on photos)

My first thought about the emulsion was that it wasn't an emulsion, but
was from degraded cell components from using petals that were too old.

However, it did separate by the next day, so it was an emulsion.

There were three yellow pigments - one that was water extractable, one
that was not extractable in water, but was in alcohol, and one that was
extractable from alcohol  with paraffin oil.  Most of the pigment was in
either water or oil, little was in alcohol, but there was some.

There was definitely yellow pigment in the paraffin oil.

I rinsed the petals after the water extraction to make sure I'd gotten
rid of all the water soluble pigment before adding the alcohol
extraction.

The alcohol/lamp oil mixture did not form an emulsion when I started
with the hot water extraction.  The water remaining in the petals was
apparently enough to change the concentration of the isopropyl alcohol
to give it slightly higher specific gravity so it separated out very
quickly.

I think I do remember seeing a faint border on the falls, but am not
sure.

ABBEY only has one stalk, & I've pretty well used up the one bloom that
was open.

- --
Linda Mann east Tennessee USA zone 7/8
East Tennessee Iris Society <http://www.korrnet.org/etis>

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