?Blue Chicken broth?

[Topanga]

Just added a can of chicken broth to dried, washed uncooked lentils and the broth has turned beautiful blue-green. I say it's fine, wife says it looks like what Lady McBeth was cooking. What gives?

[Topanga]

This is the wife and the broth was a dark blue-black color!

[tralfaz]

What kind of lentils? Do you have any left to soak with plain water?

[Topanga]

They are generic yellow lentils from Walmart and no, all were put into the soup. I rinsed the lentils and started cooking them in plain water and then added the broth, which was canned, was not dark in color itself. The water immediately turned a dark color when I added the broth.

[Topanga]

There is a remote and nearly forgotten neuron in my brain about this that I can't quite recall--I was hoping someone knew what it was all about. I'm thinking that it was a simple and harmless chemical reaction related to the beans being alkaline, and that it is a harmless sort of thing that disappears with the rest of the things that go into lentil soup--does anyone know for sure??

[phatch]

Alkalinity would do it if you had cyoanthins present. But I don't think yellow lentils have cyoanthins, or enough to produce that effect, nor are they alkaline.

Phi

[DC Sunshine]

That's totally wierd - reminds me of a scene from Briget Jones' Diary...

You didn't have a bouquet garni tied with blue string in the pot with the lentils?

[Luc_H]

I think I expected to answer this....
I have been racking my brain and searching the web to try and answer this one. This is a far fetched explanation...

First, the blueing with an alkali you have mentioned applies to blue corn when lye is added which develops the colour blue. I don't think an alkali was involved here.

lentils (even yellow) contain anthocyanin pigments which are water soluble. Depending on the chemical present this colour can range from pale yellow to deep blue.
The canned broth was probably loaded with metallic ions (tin, iron, zinc and the like). Metallic ions combined with anthocyanin can make dark blue colour when no coulour was apparent before the addition.

This is probably not the definitive answer but It's my best guess not having seen the product nor the lentils in question.

ref: Green Lentils, All About Beans and Legumes on the Worldwide Gourmet
Agris Search Results
excerpt: The formation of metallo-pigmentation and copigmentation as potential mechanisms of inking formation was investigated in peach and nectarine skin tissues. Cyanidin-3-glucoside, the most abundant anthocyanin in peaches and nectarines, formed very purple ferric complexes with an anthocyanin/iron molar ratio of two


Luc H.

[Luc_H]

Topanga, I am curious to know...
Do you happen to remember the brand name of the broth can? Do you have another can of this stuff in your cupboard?

Luc H

[Topanga]

The broth was Swanson's reduced sodium chicken broth and I had in my pantry. I bought it last winter. I was making soup for the first cool spell of the fall and yes, I have another can!

[Luc_H]

Ok Topanga,

If you are up for a little experiment (that may probably not work), I suggest you try this:

Get yourself a red cabbage and those lentils again. According to my hypothesis, both these foods should have the same family of pigment but different colour (I.e anthocyanin)

Prepare a pot with lentils the other with the cabbage with some water. Try to reproduce your lentil dish but 1/2. The cabbage, I want you to leach out the colour in the water.

Add half of the can of broth with the lentils (hopefully it reacts) and do the same with the cabbage.
If my hypothesis is correct, you should have another reaction happening with the cabbage (maybe dark green or black).

Just an idea! If it doesn't work, at least you can enjoy the lentils and lost some red cabbage and 1/2 a can of broth.

Luc H.