Pleased to Make you Aquaintants

Gluten is a staple for some, but a terror for others. I work as baker, but I've never actually understood the science behind it. So I wanted to explore how it works in bread, and later I'll synthesize some information on Celiac disease. Exciting, right?

First of all, gluten is a structural complex of proteins made up of polymers of cysteine and pockets of gliadin.

Cysteine is a sulfur containing amino acid that is the monomer of glutenin (or glutelin). The polymer form involves chains that link by hydrogen bonding at the oxygen and nitrogen positions and disulphide bonds. This gives bread its structure, and is very important in giving bread its elastic properties. The hydrogen bonds of glutenin are stabilized by hydrophobic interactions with gliadin.

This is alpha-gliadin. It is important for directing glutenin during the proofing process. It is not water soluble, so it hangs out in pockets of glutenin chains like so...

When wet, these guys create a viscoelastic matrix that holds the starch granules in place. The starch would have provided energy for the developing plant embryo, and gluten would have provided the necessary protein. In the case of flours, alas, it was not meant to be.

From what I'm given to understand (and please correct me if I am wrong fellow foodies), as bread rises, the disulphide and hydrogen bonds of glutenin attach and detach, pivoting around the pockets of gliadin as carbon dioxide is released from anaerobic fermentation by yeast. Pockets of carbon dioxide increase in volume and stretch the gluten protein matrix that merges and separates. A bread is proofed when the maximum amount of stretching has occurred, providing the softest texture of the baked bread.

In order to test whether or not your bread is proofed, forget the antique store axiom, and don't look, touch. If it's fighting you a bit, then it is under-proofed. If it gives a little (leaving an indentation), then it's proofed. You'll know your bread has over-proofed if it's sunken in on itself... and this is always a sad moment. At this point, the proteins have stretched beyond their means, chambers of carbon dioxide join, and the gases escape, leaving a wrinkled shell of its former self! If you're lucky, the fermentation will continue, and your bread may rise again!

Maillard reactions seem like a good way to start a food blog. While it is well known that cooked food undergoes a color and flavor change, the chemical reactions that occur are not.

Enter Louis-Camille Maillard.

About a hundred years ago, he published the first paper describing what reactions take place between carbohydrates and amino acids at elevated temperatures. We owe our understanding of roasted coffee, soy sauce, beer, bread, and the host of other things that we put in our bodies (and occur naturally within) to this guy. Unfortunately, these reactions are also responsible for creating acrylamides and furans in burnt or processed foods. When these reactions occur in the body or are ingested, they lead to diabetes, cataracts, and cancer. Despite these unfavorable products, we have gained much of our subjective appreciation of food thanks to these everyday reactions.

The reactions produce hundreds of different products (and can be complicated to follow), but a lot of this work was simplified in 1953 by John E. Hodge (who shares my brother's birthday).

Post WWII, the Dept. of Agriculture funded Hodge's work in order to create more palatable food with a longer shelf life on an industrial scale. Where Maillard had simply discovered it, Hodge understood and described. Since then, scientists have elaborated on these reactions, testing for variable pH, moisture content, and temperature in order to create the ideal flavors in our processed "foods."

According to Hodge, the general maillard reaction happens as such:

A carbonyl group of a sugar reacts with an amino group on a protein, producing water and an unstable glycosylamine.

The glycosylamine undergoes Amadori arrangements to create aminoketose componds

These compounds are then polymerized, rearranged, ameliorated, and converted into thousands of products.

These products produce aromas, pigments, textures, and hunger. I only bring this up because of course we can continue to enjoy food as long as it is available, but understanding the mechanisms behind it might make our food even tastier. For me, this aids my understanding of gluten, and as a baker, my life is somewhat held together by these tiny fibers of protein and starch granules.

Here's a picture of my brother.