November 12, 2013 - 3:59am
Sourdough cuts gluten?
There was a story on CBC's Ontario Morning today that goes hand in had with this story:
Sourdough breadmaking cuts gluten content in baked goods
It says:
A team of Italian scientists led by Luigi Greco at the University of Naples authored a 2010 study that showed significantly lower levels of gluten in sourdough made according to old methods.
The difference was so stark that celiacs in the study were able to consume the sourdough with no ill effects.
How can sourdough reduce gluten? Anyone know? Fermentation works on sugars - how doe it reduce a protein?
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A followup:
http://glutenfreecooking.about.com/...
The story's not that simple:
Quote "...researchers have discovered that "fully fermented" sourdough baked goods, made with a specialty wheat flour treated with specific good bacteria and enzymes did not have toxic effects on a small group of Celiacs participating in a recently published study."
Still researching...
release proteolytic enzymes that break proteins (including prolamins that cause celiacs' immunitary response) into polypeptides and amminoacids.
Of course the longer the fermentation goes on the more prolamins are broken down, but the structure of breads undergoes the same sad destiny. Prolamins include the gliadins in wheat, one of the two gluten-building proteins
bread looks and tastes on its way to decomposition.
My theory is that the gluten proteins are closely associated with other proteins and compounds that are difficult to digest. Sourdough treatments likely inactivate a whole bunch of indigestible compounds and anti-nutrients. Any fermentation is a bit like predigestion, any way.
As an example, I can't eat oatmeal unless it has been fermented or heavily toasted. If I do eat it, it feels like someone has implanted a brick into my stomach. If i eat fermented oatmeal, my belly is happy and gives me no trouble.
Mind if I ask you for a recipe for fermented oatmeal? Seems like something I should at least try once.
If you have a sourdough starter, it's incredibly easy. All I do is mix about a teaspoon or two of starter with a cup of water, mix that with a cup (~130g) of coarse cut grains (NOT rolled, although that's only my preference. They turn to mush too quickly). Leave that out at room temp overnight.
To enjoy it, add about another cup of water and cook over low heat. If I have a long week and not a lot of time, I'll reserve a bit to ferment and just keep the oat-ferment alive. I don't keep it alive indefinitely like my starter, just because that's a bit too much work for me.
If you don't have a sourdough starter, a bit of live-active culture yogurt, whey, sauerkraut juice, etc. works. If you have none of those, the coarse-grind oats are a source of cultures themselves, it'll just take a little while longer. Most oats are steamed as part of their processing, and so may not have natural cultures (although they wouldn't be too dissimilar). I always diversify my breakfasts, typically including rye and buckwheat, and maybe other things.
Never had it fermented. How is that done?
to feel like a brick in the stomach to stay off hunger for hours on end. That is why dried oat cakes were a common food on voyages to The New World. A little water and presto, full stomach, considered a good thing. Gluten is low in Oats. Also, the lab rats mice love the stuff, more balanced than the other grains.
I would be careful about making health claims as the Canadian Food Inspection Agency expects that you are able prove these claims. I think having read somewhere that gluten is reduced through long fermentation without hard evidence might not cut it.
Gerhard
I trust you realize it's not me making those claims... but the CBC did.
I meant the baker in Victoria, CBC was just reporting on his claims. We always get customers that want me to tell them that dark chocolate is good for them, my answer is to eat chocolate because you enjoy it and if they believe it is good for them well that is just a bonus.
Gerhard
If something tastes good, and isn't solely acrid, it's probably good for you. If not your body, then your more ethereal parts.
Hmmm. Not sure i can subscribe to that. Candy tastes good and it's (mostly) bad for you. Lots of people eat good-tasting salmonella-infected food. I eat tofu and it's good me me, but it tastes like... well, not much of anything, really.
I like the taste of olives; my wife doesn't. She likes marinated artichokes; I don't. Taste is too subjective.
I too have read popular articles about folks with gluten issues (even diagnosed celiac sufferers) being able to tolerate well fermented breads. I can add anecdotal evidence of gluten-challenged friends eating my own sourdough in modest quantities with no ill effect.
I have also read a scientific paper that identifies the molecular culprit(s) as a handful of relatively short strings of amino acids that have been formed from the partial digestion of much longer amino acid chains found in (mostly) gliadin but to a lesser extent in glutenin as well. (One example is PQPQLPYPQ, where P = proline, Q = glycine, and Y = tyrosine.) The 9-amino-acid toxic peptides seem to be the ones that incite the problematic immune responses in sensitive individuals.
Some researchers find hope in the production of wheat strains that only produce gliadin and glutenin chains that do not contain the offending sequences yet still have the ability to combine in the presence of water to form the gluten we work so hard to achieve.
Other researchers have been able to show that several of the bacteria commonly found in a sourdough culture will significantly reduce the concentration of such toxic peptides during normal fermentation. Unfortunately I have yet to read the sort of authoritative directions we might like to see: "Use a 1:Y ratio of sourdough starter:wheat flour, bulk ferment for Z hours at X° followed by N minutes of final proof at Q° to completely address your friend Sarah's gluten issues." But people are working on it.
However, we will probably never see a protocol that will entirely liberate us from the litigious factions that will jump onto any claim of gluten-safe wheat bread.