[evan_inquires]

For a color derived from a plant (leaves, roots, fruit) and powderized, how can the  starch content affect its shelf storage and future use?

If you know of a procedure to remove starch from the color concentrate, please share it to me...

[eugenedakin]

Hello evan_inquires,

I have alot of experience with extraction, unfortunately, I need to know the chemical or some of the properties of the dye. For example, if the dye is oil-soluble, you may be able to mix some oil-based material in your starch solution and then seperate the dye by adding water (which should dissolve the starch).  Then decant the oil off, and then concentrate the dye by boiling the oil off.

This is just a suggestion.

Sincerely,

Eugene

[ARGOS++]

Dear Evan_inquires;

It is really not easy to give you an adequate answer!

I’m "one of the last" who likes to destroy your hope for a simple and successful answer or for an easy to follow recipe, but all my and also most of “our” dyestuff division experience tells me, that you will face at least three times as much problems as different dyes you prefer to isolate   ─   Sorry!

Because the numerous different dye classes/types in nature (Carotenes and Derivates, Chlorophylls and Derivates, Anthraquinone and Derivates, “Henna”, and so on, and so on) you have to solve most the time the same problems again, but all times in different constellations.
Usually such separation work is done by all the different kinds of Chromatography, but I believe that’s not very suitable for production.

Some Hints may be anyway helpful: 

• As for some Dyes the method of Mr Eugene Dakin will work very well (for Example for Carotene; in this case also different Ethers will work), so for polar Dyes nearly “no” such extraction method will work.
• In many cases you may not have to extract the starch, and that will be if you can answer the Question about the Affinity of your Dye to starch AND to your Substrate you would like to dye. In this situation starch can even be an advantage and you have only to take care the starch will not been “eaten up” during shelf storing.
• Even “eating” the starch by bacteria can be a solution, if, - if your Dye will survive for a later easier extraction.
• But even in other situations nothing of all will do the job, because you have a very special application.

I think there are as much Solutions as different Dyes, at least till you have found any systematic.
You see we need a lot of information about your “Colors” and a lot of personal knowledge about all the dyes.

Sorry!   ─   I would like to be of more help then only that!

Good Luck!
                    ARGOS⁺⁺

[evan_inquires]

Natural colors are commonly water soluble. We can only think of removing the starch by converting it to alcohol and boil it off with water. What will be the disadvantages?

Is this a tested method already? If you know of a study using fermentation as a starch removal method from natural dyes, you can share it with me.

[eugenedakin]

Hi evan_inquires,

ARGOS++ is quite right with his entire reply, there are many ways to extract the dye. 

You mentioned that you may be able to convert the starch to alcohol and boil it off with water.  This may work only if you can have the starch molecule small enough so that it has a lower boiling point than the dye. 

The other problem that you may be running into is the possibility of degradation of the dye. When you convert the dye to an alcohol, you may also be converting the dye (or portions of it) to an alcohol, which may change the chemical to not be a 'dye' anymore. 

You could try the helpful suggestions that ARGOS++ posted.

I wish you the best.

Eugene

[evan_inquires]

Thank you for both for your replies, it widens our awareness on color extraction. We are trying to extract the purple color from purple yam ( an abundant tuber in our locale). We resorted to a much simpler step which is just extracting it on water and heating and got too much starch on our end product.
         In extracting purple or anthocyanin, what best solvent can we use? Please give me an idea on anthocyanin extraction from starch rich source. 

[eugenedakin]

Hi evan_inquires,

I am not sure how well this method works, but it may be worth a try:

http://www.csulb.edu/~bruss/documents/AnthocyaninandChlorophyllExtraction.doc

I hope this helps,

Eugene

[ARGOS++]

Dear Evan_inquires;

Natural Colors are commonly water soluble.

This is by far not true!, ─   Neither, by your Generalisation, nor in your Simplicity, except you call a very special definition of solubility your own!
I think I pointed that already out very clearly.

It is another case that you prefer to deal only with Natural Dyes, which you declare as water soluble.

To your Problem:
I believe that for such water-soluble Dyes the best method for isolation and cleaning will be the “CCC” or derivates of it like “DCCC”, “HSCCC”, “EECCC”, “CPC”, and how ever all may be called and abbreviated.

The basic method is in all cases the “CCC”, the “Counter Current Chromatography” or the “Counter Current Extraction”.

For a small overview you may study:   "History of CCC”
(There is a lot other on Yahoo!.)

For some Theory and Efficiency visit:   "Extraction: CCC and  CCC”
And also on:   "CCC & Mr. L.Craig”

And finally, that it works also for  “Anthocyanins”:    "CCC for  Anthocyanins ”
I know there are also Apparatus, where both liquid Phases are really moving, and so it is also designed for real continuous processes.

I hope this all may be of help for you.


Good Luck!
                    ARGOS⁺⁺

[evan_inquires]

Thank you again for sharing your expertise. We are simply put, overwhelmed. The process of anthocyanin (solvent) extraction alone aside from the very low color recovery, is also highly unstable and we, most of the time, didn't get our desired color range/shade. We didn't tried Chromatography separation because there is no mass production application. We tried batchwise co-current extraction for yield optimization.
The purple yam 'attractive purple' color shade still elludes us but we believe we are on tract and we're going there.