This week's dish gracepoint food science lesson is about gluten. When you eat French bread, there is a chewy texture where the starches feel like they are made of long chewy strands.
There are two proteins in flour that interact when hydrated and form gluten. When you mix around the dough (in a process called kneading) you allow the gluten to interact with other gluten molecules and form an extensive network. CO2 gets trapped in this framework and that's the basic principle behind bread. The more you mix and move around the flour, the more the gluten network develops. This is desirable when making French bread, but bad when you don't want gluten as in pie crusts. Since gluten requires hydration, you can add fats to prevent this. Shortening (hydrogenated oil / crisco) gets it's name from it's ability to "shorten" the length of gluten strands. The fat gets between the gluten and doesn't allow the molecules to interact. It's particularly effective when you add fats first and mix it in. That way the flour gets coated with oil and is "water proofed" to prevent gluten formation.
Understanding these principles allows us to manipulate food to get the desired consistency. In my next post I will talk about how you can use this knowledge to make what I (and many others) feel is the BEST BROWNIES I've ever had.