Saturday, August 11, 2012

Flour


One of the biggest components of most our baked goods is flour.  Recently though, flour has gotten a bit of a bad reputation.  What is Flour and where does it come from? What are the different kinds of flour out there? What is the difference between a wheat allergy and Celiac’s disease? What is the big deal about Carbohydrates?

The most common type of flour that we use is wheat flour. In general, there are two basic types that you will use when baking, White Flour and Whole Wheat flour.  Each kernel of the wheat plant is made of three main parts: Bran, Endosperm, and Germ.  

The Bran is the tough outer coat of the wheat kernel.  Bran is high in what people like to call dietary fiber.  Fiber is made of cellulose, a part of the plant that our bodies are unable to break down and digest.  As a result, fiber is generally passed quickly through the digestive tract with only a small amount of nutrients absorbed.  Other examples of fiber are celery, beans and nuts.  The reason why they say that fiber helps to promote regularity is essentially due to the fact that since fiber is non-digestible, it will be moved to your colon quickly.  Therefore, the more fiber you eat, the more you’re going to have to poop.

The Germ is the part of the kernel that will be used to create a new plant.  The germ therefore has a very high amount of protein, fat, vitamins and minerals.  In general, bakers tend to add wheat germ to their baked goods in order to augment the nutritional value.

The last part of the kernel is the endosperm.  This makes up over 80% of kernel and has big chunks of protein with a massive amount of starch embedded in it. Approximately 70-75% of the endosperm is made up of starch.  The proteins that you find in the endosperm are called glutenin and gliadin. When water is added to these two proteins they form gluten.  Gluten is a protein that creates a tough matrix of strands.  It is these strands that help to give structure to a lot of your baked goods.
Now, White flour is made from the ground up endosperm, the germ and the bran are removed.  There are three main categories of white flour available; pastry flour, all-purpose flour, and bread flour.  The primary difference between these types is the amount of protein.   Pastry flour has 7-9.5% protein, all-purpose has 9.5-11.5% protein, and bread flour usually has 11.5-13.5% protein content.  The reason why we generally use all-purpose flour is because it fits within the range of bread and pastry flours and can make a fairly good version of both.  There is also cake flour out there which has 6-8% protein and high gluten flour which has 13.5-14.5% protein.  As you can see, whenever you make bread you want more protein, and when you make cake you want less.  Since the proteins are used to make the tough gluten strands, it is understandable that you wouldn’t want to have a lot of gluten in your cake.  I’ve never known anyone to request a ‘chewy’ cake.


Whole wheat flour is a little different from white flour since it is composed of the entire wheat kernel.  These flours also have a shorter shelf life than white flour since the bran and germ contain oils which can go rancid. Whole wheat flours tend to have fairly high protein content at around 11-14%, but do not produce as much gluten as regular flours.  There are a few main reasons for this.  The Germ contains gluthathione (a protein) and the bran contains pentosan gum, both of which hinder the development of gluten strands.  Also, the bran particles are actually quite sharp and tend to literally cut through the developing gluten strands. 

Types of Flour
Today, there are many different types of flour available; Rye flour, rice flour, durum flour, soy flour, potato flour, etc.  These different types of flours can give you a variety of different flavors and textures.  One of the things you may want to keep in mind though is that many of these flours do not have the ability to create gluten.  It is actually because of this fact that they have become popular for the creation of gluten free products, but additional steps are necessary in order to create a stable product.  For example, a gum such as xanthan or guar must be added to many products to create a stable structure.  Think about the fact that the entire structure of your bread is based on gluten strands, then think about what will happen if they are no longer there.

Wheat Allergies and Celiac’s Disease.
Wheat allergies are pretty much the same as any other allergy.  The wheat particles are identified as a foreign object by your body and an allergic reaction ensues.  These individuals will generally experience the same symptoms as any other person who is allergic to something.
Celiac’s Disease is a little bit different. This is a genetic disorder that creates problems within an individual’s digestive tract. When someone with Celiac’s consumes any amount of gluten, it literally damages the walls of the small intestine, which is where nutrients are absorbed by the body.  As a result, this disease has actually spawned a series of gluten free products to be created.

Carbohydrates
The enemy! Or some people tend to think.  True, carbohydrates can and will make you fat, however, as I have said before, moderation is the key! In the case of flour, the carbohydrates are coming from the starch molecules that we saw are found in the proteins in the endosperm.  The starch molecules are what we would call a complex carbohydrate.  It is made up of many glucose molecules that are bonded together.  This is actually how plants store their excess glucose (sort of like plant fat cells).  I think at this point you’re starting to get the idea of where we’re going here.  Glucose is essentially the basis for the majority of our food sources. 

Now let’s talk about how sugars relate into this.  Sugars ARE carbohydrates, they are just simple ones. The difference between eating a starch and eating a sugar is based on how much energy our bodies use up to digest them.  We saw last time that sugars are easily metabolized since there is only one bond to break in disaccharides and no bonds to break in monosaccharides.  In the case of polysaccharides, there are several bonds that need to be broken down in order to fully metabolize the food source.  It is because of this fact that the sugars that are contained within them are more slowly released into our blood stream.  Having a rapid entry of glucose into our blood makes our bodies tend to store them as fat since there is far too much to be utilized immediately.  When we eat polysaccharides, the sugars are released more slowly, thus allowing our bodies to utilize them over time.  This will help prevent the glucose from being converted to glycogen and stored in our fat cells.
There is a key point here that is sort of implied.  In order for our bodies to utilize the energy that we are giving it, we need to be active!  It is great to eat complex carbohydrates since they release their sugars slowly, but if we are just sitting on the couch, our bodies will still have far too much glucose and will still be stored as fat.  There is absolutely nothing wrong with a nice pasta dinner with some nice artisan breads, unless you fill up then sit around doing nothing for the next few hours.