10% Oat Bread Sourdough WW

10% Oat bread

The health properties of Oats have been known for quite some time.  A lot of science has focused on the ability of oats to lower serum cholesterol.  Oats contain over 9% fiber, much of it water-soluble, and this is one way it tends to pull the cholesterol from the GI tract and excrete it from the body.  Its protein level is about the same as wheat, around 13%, and its ash (mineral) content is somewhere between 2-3%.  Starch makes up the bulk of what's left.

When reading about oats you will likely run across the use of the term "beta-glucans".  This is the main component of oat's soluble dietary fiber.  It is a linear polysaccharide found mostly in the cells walls of the grain's endosperm.  The amount of this substance varies with the variety of oats and where it is grown, but it can make up 1/3-2/3 of the entire amount of fiber in oats.  Scientists have focused on beta-glucan as the main cause of oat's cholesterol-lowering ability.  It has this effect, many studies say, because of the way it affects viscosity.

Bear (down) with me as I talk about poop.  As a nurse, I don't find this too off-putting, but others might find it so. 

Making Oat bread when there is still a partial loaf of buckwheat bread to eat

whole wheat : oat flour
90 : 10

Just before adding the salt

Although other bran fiber-rich grains will have a similar effect of drawing water to the faeces, adding to the bulk and aiding elimination, they can't all claim to have the same effect on cholesterol as oats.  According to Sungsoo Cho, who wrote the book "Dietary Fiber", Oat bran is

"not a true bran and is in fact highly enriched with the thickened outermost cells of the endosperm (subaleurone cells).  The walls of these cells are considerably thicker than those of the general endosperm cells and are rich in mixed-linkage beta-glucans."

And what I find particularly intriguing is that, whereas the bran of many grains will have an anti-nutrient effect on some minerals, scooping them up and excreting them before they have a chance to be absorbed through the  GI tract, the arabinoxylans in oats have precisely the opposite effect: calcium and magnesium are better absorbed.  Huh.

Furthermore, oats have a positive anti-oxidant ability.  Not only will it scoop up cholesterol in the GI tract, its anti-oxidants will scoop up the free radicals in the body and chelate dangerous active metal ions.  This grain has also been associated with greater satiety and better insulin-response -- again, because of the way viscosity is increased in the gut.

 But viscosity, although apparently a good thing in the gut, may not be the best thing for making good bread.  How will adding 10% oat flour change a whole wheat flour dough?  And is 10% oats even enough to have a positive effect on health?

Health Claims
There are legal issues at stake: for products containing oat supplementation to carry the health claim that it will "reduce the risk of coronary heart disease" by reducing cholesterol, it must have 0.75g Beta-Glucans per serving.  How does my bread stack up?

With 100g of oat flour, I should have around 9g of fiber.  The beta-glucans compose about 3-6g of this.  Each of my 2 breads will have about half of that again, or 1.5-3g of beta-glucans.  With 20 slices per loaf, give or take, that means I'm only getting 0.075-0.15g of it per slice.  I'd have to eat 5-10 slices of this bread to get the health benefits we're talking about (1/4-1/2 a loaf).  (Or increase the amount of oat flour I put into the loaf: to ensure I'd get 0.75g per slice of bread, I'd need to start out with ten times the amount: 1000g oat flour, for 90g of fiber, 30-60g of beta-glucans, 15-30g per loaf, with about 20 slices.  But that would leave no room for any wheat flour!  So you see, if you find a bread that makes this claim, it is probably an extruded bread supplemented with oat beta-glucans -- highly processed -- and is probably not whole oat grain.)  We'd be better off with oatmeal porridge.  Paul Pitchford, in "Healing with Whole Foods" says that

"Oat flakes are nearly as nutritious as whole oat groats, as they have been only lightly processed by rolling and steaming; they are the only whole-grain cereal that many people eat."

Results
I find that oat flour feels quite different from many other grains that have been milled fine.  While I do not run it through a sieve, it might be a good idea, when mixing it with other flours, because it has a tendency to clump together.  I have only added 10% to this loaf, and it had a marked effect.  The dough tended to sag under the normal 75% hydration.

And the taste, to me, was a bit more bland.  Whereas with the addition of buckwheat flour I was worried the flavour would be too pronounced, here I should have been worried that the flavour would be flattened by the oat flour. 

Notes to Myself

• It will be impossible to add enough whole oat flour to a whole grain wheat bread to make it legally "heart healthy" (unless it is all oats, but then you wouldn't have a recognizeable bread). 
  
  But add oat flour to your bread anyway, for its many other real benefits (e.g. anti-oxidants).  It will change your stool.  It will change your life. 
  
  And because there are lots of real benefits, eat oatmeal porridge regularly too.