The Fresh Loaf

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Buckwheat Batter Purple

Abe's picture
Abe

Buckwheat Batter Purple

Making a naturally fermented buckwheat bread using white buckwheat groats. The batter has been resting overnight and the top layer has turned purple. I understand it to be fine but need some reassurance. Why does this sometimes happen and other it doesn't? Is it oxidation or some other property of buckwheat? 

EDIT: Been googling. Think it's called Ninhydrin. Some kind of compound in buckwheat that can give it a purple colour. At least that's what I hope it is. 

happycat's picture
happycat

Actually sounds v cool. My wife loves purple and orange. Would make an interesting swirl bread maybe with half with some rye malt :)

Abe's picture
Abe

Just the part exposed to air. Must be some sort of reaction/oxidation or similar. I think it's perfectly normal but nevertheless skimmed most of it off. What I couldn't remove it disappeared when mixed. Trying out an idea for the naturally fermented buckwheat bread. We'll know soon enough if it's worked. I've seen this purple colour a few times but it's intermittent. One often sees it if you soak buckwheat the water can turn a purple hue. some kind of natural colouring.

alcophile's picture
alcophile

Can you post a link to the reference about ninhydrin in buckwheat? I used to work at a company that specialized in protein analysis and modification and one of their early big sellers was ninhydrin. It was (and still is to some extent) used extensively in protein analysis and forensic science. It reacts with amino acids and other amines to give a purple color. I used it a few times and it will stain your skin purple if you happen to get any on it.

Ninhydrin was so important to the early success of the company I had worked for that a metal sculpture of the molecule hung in the entrance foyer.

Abe's picture
Abe

Gotta admit I didn't read through it properly. Once I saw it normal that was good enough for me. Whatever light you can shed on this i'd be most interested. Here is the website and excerpt. 

https://www.tandfonline.com/doi/pdf/10.1080/00021369.1971.10860168

During an investigation of non-protein amino acid fraction of buckwheat seeds, several unusual spots, giving rise to a yellow color with ninhydrin which subsequently turn purple on paper chromatogram, were observed.

Ilya Flyamer's picture
Ilya Flyamer

To me the excerpt reads like some fraction extracted from buckwheat gives rise to yellow/purple colour when reacting with ninhydrin - not that ninhydrin is contained in buckwheat.

Abe's picture
Abe

But not very clear, at least from that one paragraph, what they were doing. When I didn't see the colour was associated with mold or bacteria I went ahead and proceeded with transferring the buckwheat batter to a loaf pan. 

I read it as it's coloured with ninhydrin coming from the plant itself. 

I am curious as to why it sometimes happens. When researching if anyone else has experienced this they often [falsely] attribute it to mold. I'm quite sure it isn't though. 

alcophile's picture
alcophile

Abe, I'm sorry I couldn't respond sooner. I saw that article, too. As Ilya, mentioned, the researchers found that a non-protein amino acid fraction gave a positive reaction with ninhydrin. The characteristic purple color developed on the paper chromatogram. While not as well-known as the amino acid test, ninhydrin can be used for other amines.

The article is a classic example of compound isolation from plants. I don't know how far you read, but they used over 65 liters of dilute ammonia water to collect 1310(!) 44-mL fractions. Each fraction was analyzed by paper chromatography (a slooow process) to detect the compound(s) of interest. I pity the poor graduate student! And we think that some of our bread-making processes are laborious.

Abe's picture
Abe

To be honest I didn't read much of it at all. Had just uncovered the bowl after the ferment to be greeted with the suspicious purple colour. I was scanning for information as to whether it would make me ill. I am no scientist and have never heard of ninhydrin before. But from the gist of the article I could make out they weren't talking about bad bacteria affecting ones health negatively. 

All that aside I did learn something else about the mechanism of a spontaneous ferment buckwheat bread and why it works so well. Also learned about the best approach for this bread. I'm no graduate student detecting compounds but I still learned something from the practical experiment. Just like our ancestors who knew nothing of bacteria and yeast still managed to figure out the whole process. 

Hope I gave you something interesting to read! 

Mini Oven's picture
Mini Oven

http://www.eberhardprinz.de/blog/?p=11688

Did you know that in the 1700's buckwheat was grown mostly for dye?  Different parts of the plant give different colors.  The hulls are known for purple.  Lots of hits in German under buchweizen farbe.  Try: buckwheat coloring or buckwheat dyes.  Also: natural plant dye buckwheat 

Abe's picture
Abe

Google Translate...

REAL BUCKWHEAT, FAGOPYRUM ESCULENTUM, NATURAL COLOR FOR WOOL AND COTTON05.13.12 | No Comments

 

DYE PLANT FAGOPYRUM ESCULENTUM , REAL BUCKWHEAT,
HEATHER (N) KORN, HEATHER

Fagopyrum esculentum, buckwheat, dye plant
Beech nuts, buckwheat, fagi fructus
Plant family Knotweed (Polygonaceae)
engl :, Buckwheat, Fr .; Sarrasin, Blé noir, it .: Grano saraceno, Spanish .: Alforfón, Trigo sarraceno

Buckwheat, Fagopyrum esculentum dye plant, dye plant

Real buckwheat, Fagopyrum esculentum , is an annual, frost-sensitive, approx. 60 cm high plant with white to pink flowers. During flowering and ripening, the initially green stems turn red.
The botanical name comes from the Latin Fagus, beech and the Greek Pyros, wheat. The shape of the buckwheat fruits corresponds to that of the beech nuts ( Fagus sylvatica fruits ) - hence the reference to the beech tree. Buckwheat is not a type of cereal, but belongs to the knotweed family. However, the fruits are used like cereals.
Buckwheat comes from Asia and reached Western Europe via Russia. The German and Romanesque plant names give an indication of the origin, namely link the plant with Saracens (= pagans). Since the plant thrives on dry sandy soils and is grown in Germany in heather areas, heather grain was probably made into heather grain.

In Germany buckwheat is first mentioned in writing from the Leinetal in 1380.

COLOR PROPERTIES OF THE PLANT COLOR

Parts of plants for coloring: straw, stems, leaves, flowers, fruits

Dyes: fagopyrin, quercetin, rutin

Buckwheat was used for coloring in the 18th century.

The fresh stems were colored tobacco brown with poisonous bismuth stain. Otherwise, the stems, leaves, and unpeeled seeds dye unstained wool and cotton each yellow. An orange tone is said to have been achieved with iron salts. The leaves turn yellow in the alkaline range and orange in the acid range when acid is added to the dye bath.
In the past, dry buckwheat straw was also used for dyeing.

Red-brown and green tones are reported from the coloring with the inflorescences

In the literature it is described several times that fermented stems were colored blue or blue-gray. Attempts that were later carried out to color buckwheat blue were unsuccessful.

The stems and leaves of Tartar buckwheat, Fagopyrum tataricum can also be colored yellow.

CULTURAL USE

The peeled buckwheat is served as a side dish in the Eastern Bloc, like rice in our country. It is often used for soups. The Russian blinis contain buckwheat flour, among other things. The galettes in Brittany, France, are largely made from buckwheat flour (Blé noir = black flour). Large quantities of
buckwheat flour are used in noodles in Japan and Korea . In Germany, before the introduction of the potato, buckwheat was an important staple food. Oil can be extracted from the fruits. The leaves can be prepared as spinach.

The flowers are suitable for bee pasture.

Buckwheat beer was brewed from buckwheat seeds.

Today buckwheat is used as an intermediate seed for soil improvement and weed suppression in German agriculture. Buckwheat, Fagopyrum esculentum , has red stems during flowering and ripening. (Picture above)
Buckwheat, Fagopyrum tartaricum dye plant, dye plant
If the cultivated field appears green and the stems are green during and after flowering, it is mostly Tartar buckwheat, Fagopyrum tataricum , which is not quite as sensitive to frost. (Picture next to)

MEDICAL USE

In folk medicine, buckwheat seed porridge was used for strengthening. The tea made from the herb was mostly used as a gentle sleep aid.

Buckwheat played no role in medicine until the late 1970s. Then it was discovered that the buckwheat herb has an average content of around 5 percent rutin, 4 to 12 percent in the flowers and 2 to 8 percent rutin in the leaves (quercetin-3-rutinoside). The flavonoid rutin is important, for example, in the treatment of chronic venous insufficiency. Rutin improves the microcirculation in the blood vessels and positively changes the vessel walls.

A cure with buckwheat tea is suitable to prevent circulatory disorders and varicose veins.
Buckwheat is used as a homeopathic remedy.
In animals, feeding with the green of buckwheat as well as the peel of the fruit can cause phototoxic reactions caused by the fagopyrin it contains. This is why peeled buckwheat is used as food.

FURTHER INFORMATION

Dye plants for natural fibers - wool and silk, cotton, linen

[spaces were photos that haven't copied over properly]

Abe's picture
Abe

Didn't need to skim the top off the batter and waste any after all. Made enough to fill a 1.5L loaf pan and after removing the top layer it ended up not enough. It has baked up very nicely though. 

naturaleigh's picture
naturaleigh

I wonder if you got some heirloom purple barley mislabeled as white or you got some mixed in?  I'm assuming, though, that the groats would have looked darker to you at the outset, so maybe not.  I just tried heirloom purple barley for the first time as part of my most recent Vitacost order, which included this Shiloh Farms grain--the berry is actually a medium brown color with some lighter and darker berries here and there.  I cooked it up as part of an add-in for chili and it definitely turned the cooking water a purple/gray color.  Another possibility perhaps.

Abe's picture
Abe

Just spent some time on google translate typing in everything it says on the box. They're adamant it's white buckwheat. However it's always a possibility I suppose. I've had it before and so do other people report it (even though they jumo to the wrong conclusions). It must be something in the buckwheat. 

My friend, Richard, over on breadtopia recently tried purple barley in a Hamelman recipe. Do you have Hamleman's book? Looks like something well worth trying. Well lets face it... all Hamelman's recipes are well worth trying. 

happycat's picture
happycat

Dunno if it's the issue but in my rye kernels I usually get a few still in husk. If the husk causes blue, maybe some slipped in.

Abe's picture
Abe

and you know something... When washing and soaking them in water I did see a few which did look like they still had the husks on. Just a few here and there mind you. Do you think that'd be enough for the reaction? Perhaps the long soak, ferment and high hydration was the perfect catalyst. 

naturaleigh's picture
naturaleigh

I hadn't thought to use it in bread, but your post has given me some definite ideas!  I enjoyed the taste and hearty texture the way I prepared it (soak/boil/drain) so I imagine it would be a great add in for bread, although it took a fair amount of cook time since it is a pretty hard grain so a serious pre-soak time would be required for bread.  I'm assuming there are extra nutrients in it as well given the color.

I will likely have to wait to try this experiment until after Christmas.  Strangely enough, although I am a cookbook addict, I do not, yet, own any of Hamelman's bread books--I do have several bread books tagged to my wish list (including Laurel's Kitchen) so I might get a nice surprise or two at Christmas.  Fingers crossed.  

Mini Oven's picture
Mini Oven

if the purple layer would have baked out or remained to make an interesting crumb swirl or zigzag.

 Something like a roll up, split and twist like a babka shape.  

Or a focaccia experimenting with different pH glazes to make a patchwork bread effect.

I might be able to find it growing nearby as the farms around here often use "green cover" to prevent erosion.  It would be interesting, say for instance if the leaves, hulls and stems were laid on the proofing dough, then removed before baking to see if the leaves left a color impression.  Painting a bread canvas.  Hmmm.  

Abe's picture
Abe

So no rolling up. This is my go to buckwheat bread recipe technique. I think it makes the best buckwheat bread. Don't follow the recipe exactly as it's easy enough to eyeball most of it. But the technique is the same...

  • 500g raw organic buckwheat groats soaked in 600ml water for 12-24 hours. 
  • Add salt according to taste and blend with enough water to make a batter. 
  • Cover and allow to ferment for 24 hours. 
  • fold in any additions you want and transfer into a prepared loaf pan and bake at 350°F for about 80 minutes or until done - it needs quite some time. 

The video attached is a very good one. She bakes it straight away but I like to give it time to rest between portioning out and baking. About an hour. Both ways work very well.