The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Soaking whole wheat- Phytic Acid

inlovewbread's picture
inlovewbread

Soaking whole wheat- Phytic Acid

I have been doing some reading on Phytic Acid and Phytates in whole wheat. You can read about it here and here

I don't know why I missed this in the past, but now I'm all freaked out and feel like I need to soak all my fresh ground whole wheat flour before using it! That means a lot of re-working of all my favorite recipes. 

I don't see a whole lot of information on it on TFL (although Peter Reinhart's methods include this step of soaking in Whole Grain Breads). I have read a few threads on this site and elsewhere relating this method with celiac disease/ rise of celiac disease in the years after commercial yeast became available- a lot of interesting information on that, but that's a separate subject.

So I guess my question is, does everyone else here know about this 'soaking-to-rid-whole-wheat-of-phytic-acid' technique? If so, why aren't more people soaking their flour first? Obviously you don't need to worry about soaking in sourdoughs (because of the lactic acid in the culture) but I don't see much talk about it for sandwich loaves or whole wheat loaves using commercial yeast. Any thoughts?

 

 

 

Yerffej's picture
Yerffej

I am fully aware of phytic acid and the issues that surround it.  This is a very big factor in my baking almost all sourdough breads.

Jeff

Here is another link you may find to be informative:

http://www.westonaprice.org/Be-Kind-to-Your-Grains...And-Your-Grains-Will-Be-Kind-To-You.html

inlovewbread's picture
inlovewbread

Thanks for the link, that's a great resource, a lot of information in one spot. Especially all the articles on soy! I wish everybody would read that.

All the breads I make are leavened by sourdough, eliminating the soaking dilemma, except for sandwich bread. We just prefer a non-sourdough sandwich loaf. And I'll just have to figure out how to adjust my muffins, etc. to soak or sourdough. The benefits will justify the extra effort.

Sustainable Eats's picture
Sustainable Eats

I'm also fully aware of it but my family won't eat sourdough often.  I finally came to this:  http://www.sustainableeats.com/2009/03/30/100-whole-grain-bread-soaked/ as our daily bread since it's 100% whole wheat but soaked and everyone loves it.

I also soak my pizza dough and pancakes:  http://www.sustainableeats.com/2009/03/22/whole-grain-buttermilk-coconut-pancakes/ and crackers:  http://www.sustainableeats.com/2009/11/27/crispy-rosemary-flatbread-crackers/ or http://www.sustainableeats.com/2009/05/21/sustainable-crackers/

overnight to reduce the phytic acid.  For any baked good like cookies, etc I just use flour that I've made from sprouting the grains, dedhydrating and then grinding.  I can't get any non-yeasted thing to turn out good enough to please my picky palate otherwise.

It takes some preplanning but still not as much as making and feeding a starter.

Edthebread's picture
Edthebread

By my reading of the document that was in the link in the first posting, the phytic acid in wheat or rye flour is gone within 2 hours of soaking.  As most bread takes this long to rise and proof, will it not be gone before the bread bakes?  Am I missing something?

Sustainable Eats's picture
Sustainable Eats

It may be somewhat reduced after 2 hours but it's not gone.  WAP recommends soaking for 8-12 hours or more.

Futterbudget's picture
Futterbudget

I soak all our whole grain flours to get rid of phytic acid, using the Nourishing Traditions method for muffins and pancakes (soaking in kefir).  

Most of the time, I just make sourdough, since that's an easy and tasty solution, but I've played around with soaking flour for a yeast-leavened bread too.  The best results I've gotten have been with Scottish Sponge Bread, an overnight started dough from the Laurel's Kitchen Bread Book.  

Sustainable Eats, thanks for the link!  I'll try your recipe too!

eehmoore's picture
eehmoore

I have had good success adpating Reinhart's 100% whole wheat sandwich bread to a soaked version.  In the soaker I substitute (by weight) buttermilk and leave on the counter overnight.  In the biga I substitute yogurt whey for about 1/3 of the total water (by weight) and retard in the fridge.  Itry to soak both for 18-24 hours.  I do not soak the flour in the final dough, however the amount by weight is a fairly small percentage of the final dough and our family is not prone to gluten of digestive issues, so I don't worry much about it.

I am loving all the links previously posted.  Great info.

subfuscpersona's picture
subfuscpersona

...the conditions are properly followed. Two conditions must be met - the pH of the liquid and the temperature during the soak.

This graph shows that phytic acid can be virtually eliminated in wheat and rye with a one hour soak in a somewhat acidic solution where the soaking water is maintained at 45 Centigrade (113 Fahrenheit) for the duration.

I've never been able to find reputable, scientific studies that show that longer soaking at lower temperatures achieve the same result.

In addition, I've never been able to find reputable, scientific studies that show the pH values of buttermilk, sourdough starter, homemade whey or other liquid ingredients typically used by home bakers interested in this topic. Without this info I cannot determine if these liquid ingredients have the correct pH value of 4.5 that is required to achieve significant phytase reduction in one hour.

If anyone has good data (from scientific journals please!) that they'd like to contribute to this discussion, please post the references. I'd be very interested.

MissingDanishBread's picture
MissingDanishBread

...you on your path of researching this subject.

Sourdough and cereal fermentation in a nutritional perspective http://www.sciencedirect.com/science/article/pii/S0740002009001749 This might be a good one to read because it talks about the effects of soaking/fermentation/sourdough leads to "They include acid production, suggested to retard starch digestibility, and to adjust pH to a range which favours the action of certain endogenous enzymes, thus changing the bioavailability pattern of minerals and phytochemicals."

You want to know the pH value of buttermilk (and thus other cultured products).  It is less than 5, probably more like 4.4 pH.  Compositional and functional properties of buttermilk: a comparison between sweet, sour, and whey buttermilk. (https://www.ncbi.nlm.nih.gov/pubmed/16428621).  Also, "Engineering Tool Box" website also lists buttermilk at 4.4-4.8.  In addition, FDA also has a document about listeria and a section about listeria not growing when the pH value is equal to or less than 4.4 and goes on to list ReadyToEat foods that generally do not support the growth of listeria and has cultured milk products (yogurt, sour cream, buttermilk) on that list. https://www.fda.gov/iceci/compliancemanuals/compliancepolicyguidancemanual/ucm136694.htm

Your concern for temperatures is also valid.  I don't know what the optimal soaking/fermenting temperature is but a local baker has spoken with me about her sourdough breads (basically made with Tartine method) and how those with gluten issues can eat them.  She said that when they upgraded her bakery from house to an actual bakery they were excited because the wanting to be able to better control and time the rise with the use of the big refrigerators.  However, when they let their loaves rise in the fridge, their customers reported tummy upset, and they had to go back to rising at room temperature (which definitely changes with the seasons).  So temperature has a lot to do with this subject!  I have no specific answer, but the following article might lead you in the right direction.  The sourdough was fermented at 98.6 F which is lower than the 113 F that your chart relates, but still not a room temperature (which most people utilize).

Here (http://www.sciencedirect.com/science/article/pii/S0168160503000722) is an article on sourdough fermented at 98.6 F (which is much higher temperature than what most bakers do) with a "marked decreased (64–74%) of the Na-phytate concentration was found compared with the unstarted dough. The sourdough started with L. sanfranciscensis CB1 cells was re-used for several times and the phytase activity was maintained to a considerable level." I know it is not measuring pH, but an interesting article to support the claim that sourdough is more nutritious than bread made with store bought yeast. 

Other interesting articles related to this subject.

Strains of Lactic Acid Bacteria Isolated from Sour Doughs Degrade Phytic Acid and Improve Calcium and Magnesium Solubility from Whole Wheat Flour  http://pubs.acs.org/doi/abs/10.1021/jf000061g

For those interested in glucose: In Situ Production of Exopolysaccharides during Sourdough Fermentation by Cereal and Intestinal Isolates of Lactic Acid Bacteriahttp://aem.asm.org/content/69/2/945.short  "It was remarkable that formation of glucan and fructan was most frequently found in intestinal isolates and strains of the species Lactobacillus reuteri, Lactobacillus pontis, and Lactobacillus frumenti from type II sourdoughs."

MissingDanishBread's picture
MissingDanishBread

The Influence of Soaking and Germination on the Phytase Activity and Phytic Acid Content of Grains and Seeds Potentially Useful for Complementary Feedin (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.2002.tb09609.x/full)

Certainly there are arguments for and against.  It is hard to know for certain.

MissingDanishBread's picture
MissingDanishBread

...I found a conflict of interest.  It was money backed by Nestle.  Not that it erases the research, but it is a possible conflict of interest.