Showing posts with label Glycemic Index. Show all posts
Showing posts with label Glycemic Index. Show all posts

28 October, 2009

Sourdough, funny tummies and the Glycemic Index.

After spending time in Catalonia and Scandinavia this year I bought back home with me, among many other memories, a delight in the crusty baguettes  of Barcelona and the massive array of whole grain and rye breads in Oslo and Avica (  a village just across the Norwegian border in Sweden).

After that -- I became a bit of a bread snob and nothing I can track down here could match my overseas experiences. Even at those boutique bakeries that will charge you maybe a hefty  $6  or more for a loaf  of bread came any where near my baked bread experiences in Europe.

So , no stranger to bread baking, I started  up the routine of baking bread  on a regular basis. However, since I was keen to keep to a Glycemic Index regime, the complication with eating bread (many breads will register a GI of around  100) is that it has a high GI  and to efollow a GI diet (the diet that is now recommended for diabetics) means you want to eat foods that are low GI.

Going  sour

The irony is that sourdough bread -- even white  flour sourdough bread -- has registered consistently   with a low GI (ie: under 60). The Glycemic Index has Sourdough Rye bread rated at  48 and Sourdough Wheat bread at 54. This means that the Carbohydrates  in sourdough  bread  break down slowly  during digestion, releasing glucose gradually  into the bloodstream.

When I started back baking bread I took these figures to heart and created my own 'sour dough' starter  in place of using commercial bread baking  yeast.


 Sour dough starter
I won't go through all the challenges this may present to bread baking -- especially in Australia where our flours are amylase-deficient. (Amylase = the enzyme that breaks down starches) To make up for this failing, which does not impact on the rising of   yeasted breads, you need to add a trace of diastatic malt  to Australian  flours.

Anyway, by trial and error and a few online forums -- I've been baking sourdough breads every two days or so for the last few months. The bread is fantastic to eat, and we consume every last crumb.I doubt that I can go back to eating 'normal' breads ever again. This is a very different experience of taste and crumb.

If you know your GI chomp law, you'll also know that 'sour' foods -- those that are acidic , like yogurts and vinegars and sourdough breads -- if consumed as part of a meal will  reduce the GI value of the whole meal! That's synergy for you:You can eat high GI foods but in combination with the sour flavoured dishes on the menu, these other food's GI ratings will be bought down


So I'm happy as a pig in  wheat field.

Gluten Intolerance

But there's still more to the story of sourdough and that concerns gluten intolerance. As it so happened, while I'm baking up a storm my daughter was diagnosed with Coeliac disease . Coeliac disease is caused by a reaction to gliadin, a prolamin (gluten protein) found in wheat, and similar proteins found in the crops of the tribe Triticeae (which includes other cultivars such as barley and rye). It's a gross inconvenience to be Gluten intolerant as so many foods in the Western Diet have wheat in them.

So if you are gluten intolerant it's no hamburgers, batter, biscuits, pasta, cakes...or bread for you..

However, it also turns out that , as recent research indicates  breads raised with sourdough reduced the gluten content in the flour by massive degree: In one study of sourdough fermented breads:
All fermentation batches (that is, everything but the yeast bread) reduced the gluten significantly. The second through fifth batches reduced the gluten by 73%, 83%, 93%, and 98% respectively. However, the final group, using the L. sanfranciscensis and both enzymes, reduced the gluten drastically -- from the yeast bread’s nearly 75,000 parts per million (ppm) to a miniscule 12 ppm, well below the threshold making it safe for those with celiac disease. With carefully-selected lactic acid bacteria and two enzymes, the team created a 100% wheat bread safe for people with celiac disease to eat.
This research was specific to one strain of sourdough so it's not conclusive across the (bread) board. Sourdough is first made by captured wild yeast in  the air ( such as the air in my kitchen) and growing them in a culture medium -- water and flour. So the constituents of one person's or place's sourdough will differ from another's.

It should also be pointed out that , while I do, many sourdough bakers don't rise their bread for 24 hours and the research method  allowed for a day long rise so that the sourdough could work on the proteins in the flour.(It should also be pointed out that if you  educe all gluten, your bread won't rise.)

But when you begin to consider further the  challenge this research presents  you begin to question a few assumptions that underpin our standard reading  of what made  "Western Civilisation" happen.   Wheat made "Western Civilisation" happen. The Fertile Crescent in Asia Minor -- our real "Garden of Eden" -- was a wheat field. And we've been growing and eating it --and changing our societies so we can grow and eat it -- ever since.

Grain made us what we are today. In Asia it was rice. In the Americas it was corn. In Europe it was... wheat.

But all wheats aren't the same. Therein hangs a great history tale which is related in this excellent essay by Katherine Czapp --The Case for Rejecting or Respecting the Staff of Life

I'll leave it to you to study the piece. However, while there are many types of wheat,which when milled create flours with different attributes   there is also industrial processes that have , especially under capitalism,. Czapp writes:
With the advent of the Industrial Age, parts of the world destined to become the wealthiest empires--such as Great Britain and the United States--eventually gained reputations as nations that produced the worst bread. One could lament about it, joke about it, rage about it. . . but not much could be done about it, and certainly not on a scale necessary to provide excellent bread (or other foods, for that matter) to every citizen. But that, of course, is the point. The industrial scale is not the human scale, the scale of the artisan baker, cheesemaker or small farmer. The wealthy nations attracted many laborers from the countryside at home, and from towns and cities abroad, all wanting relief from poverty and various other serious privations. For better or worse, the people needed to be fed, and the fact that their bread was insipid, their milk watered, did not strike officials as a matter of first importance. 
While we now assume that our commercially available bread is not adulterated, we nonetheless are being fed a product that is a long way from past modes of preparation:
Mechanized bread production lines have evolved over time to include three main dough mixing variations. The first is the continuous mixing method, introduced in the 1950s. By the mid 1970s, this rapid production method accounted for 60 percent of all commercial bread produced in the United States. With this process, all ingredients are added at the beginning of a cycle and the slurry of flour and yeast and "improvers" travels via conveyors without pause to the oven. Any proofing (rising) occurs there. An early television commercial for WonderBread highlighted the fact that it was made from a batter, not from dough, "so there are no holes in the bread!" Bread made in the continuous mixing method more resembles cake in texture, with a soft texture and no fermentation flavor or aroma. This method has generally become much less popular today because of the drab quality of the final product and because of income lost during breakdown periods when entire batches had to be discarded if repairs took longer than 20 minutes.
A serious change in bread-making techniques occurred in 1961 when the Flour Milling and Baking Research Association at Chorleywood, Hertfordshire came up with a method to speed up production of raised bread for industrial manufacture. Called the Chorleywood Bread Process (CBP), the method depends on high-speed mixers and chemical oxidants along with solid vegetable fat, lots of commercial yeast and water, which produces a loaf of bread from flour to sliced-and-packaged form in about three and one-half hours. Low-protein soft wheat grown at home in Britain can be used in this high-energy input method, dispensing with the expense of importing high-protein bread wheats from abroad. 
And the story gets even worse. But I'll leave you to read it. Czapp argues  that the modern  industrial method of producing bread -- with yeasted rising over and done within a twice -- could contribute to the now pandemic incidences of Coeliac disease.

But I guess, the jury  has yet to rule on the details....