What is: Protein Chemistry
... and why should I care? Well, if you enjoy your bread to hold together when you make it instead of flopping around, you should be thankful for the protein lattice that is holding it together! There are many ingredients that contribute protein to the overall mixture (outlined in the Baking Overview). Between flour, milk and eggs, there is plenty of protein to go around. The chemistry behind how these proteins go from powder or liquid to form a tall, proud loaf of bread is quite amazing.
Milk contributes lactose to the protein lattice, while eggs are rich in a number of proteins that normally go to keeping the baby chick healthy. While both of these contribute to the overall protein structure, they are not the most important factors at play. To find find this binder, we must look away from the wet ingredients and place a careful eye elsewhere.
Milk contributes lactose to the protein lattice, while eggs are rich in a number of proteins that normally go to keeping the baby chick healthy. While both of these contribute to the overall protein structure, they are not the most important factors at play. To find find this binder, we must look away from the wet ingredients and place a careful eye elsewhere.
Flour: The Protein King
The biggest contributer to the protein backbone is flour, hereby dubbed the protein king. And what is this ingredient's claim to the throne? Flour contains two very important proteins, known as glutenin and gliaden which are present in the initial wheat and grain. When these two come together, they create a composite known as gluten, which you may have heard of. Gluten gives the dough strength: the strength to rise above and become something fantastic. The carbon dioxide created by leaveners gets trapped by this strong protein lattice, resulting in a structural masterpiece that holds its shape during and after baking. Without each of these pieces, the overall structure would fail! Proteins need leaveners, and leaveners need proteins. Together, they form something truly amazing.
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Types of Flour
There are a large variety of flour produces used for baking. A few of the more common ones are listed below. Typically, the thing that defines a flour is its protein percentage, which generally ranges from 7-16% depending on the flour. It can be higher or lower than this, but that is the typical range. A few commonly used flour types are listed below.
- Bread Flour typically has a protein content of 14-16%, putting at the top of this list.
- All-Purpose Flour has a slightly lower protein content of 10-12%. As the name suggests, this is perhaps the most common type of flour with a midrange protein content. While it can be used in almost any recipe, there are often better choices. With a protein content right in the middle of the spectrum, however, it is never unwelcome!
- Pastry Flour has a protein content of ~9%. As the name suggests, most bakers use this type of flour for pastry making where a slightly lower protein content is desired.
- Cake Flour has a lower protein content of 7-8%. Cakes are much lighter and fluffier, which results in the need for a lower protein content.
Pastry and cake flour are less common than all purpose flour, but can be replicated by a nifty trick. Mixing in corn starch, all purpose flour can be "diluted" to have a lower overall protein content.
Knowing what you are baking and which flour is the right one for the job is essential in the creation of perfect baked goods! You would never want the high protein content of bread flour in your cake, as the result would be tough and chewy. Similarly, you would never want cake flour in your sourdough, because it would not have correct texture and overall strength that we've come to expect of our bread. |
Tell me About: Alternatives to Gluten
Gluten allergies are truly tragic, but can be worked around. There are a number of gluten-free alternatives that allow those suffering from gluten allergies to still enjoy baked goods. The protein content flour, which is derived from wheats and grains, can be substituted by any number of other protein sources. Some common ones include rice flours, tapioca starch, potato starch, xanthan gum, as well as many others. There are plenty of gluten-free mixes sold as alternatives to flour that can provide the same structural protein lattice to breads and cakes alike. So never despair, as there are always alternatives!
References
- A Guide to Binders in Gluten-free Sourdough Baking. Cultures for Health, Web. 7 Mar. 2014. <http://www.culturesforhealth.com/guide-binders-gluten-free-sourdough-baking>.
- Stewart, Kelly. The science of baking: Kitchen chemistry. Culinate, 2009. Web. 7 Mar. 2014. <http://www.culinate.com/articles/features/baking_chemistry>.
- What's the Difference? Cake Flour, Pastry Flour, All-Purpose Flour, and Bread Flour. The Kitchn, Web. 10 Mar. 2014. <http://www.thekitchn.com/whats-the-difference-cake-flou-74565>.