The Molecules of Food!

Today in class we started looking at the molecules (and ions) that make up food. We're going to spend a few days looking at these so we can relate the behavior of macroscopic foods to the microscopic molecular changes that take place during food preparation. We'll look at 4 main groups:

Water - Most food is mostly water. Most of life (as we know it) is mostly water. Water is a tiny molecule that is bent, so one end has a more negative local charge and the other end has a more positive local charge. {That last part's not a bad definition of "polar".} This makes water molecules stick together. (Opposites attract...) Water dissolves things that are charged or polar.

Inorganic components - salts, minerals, and a few other assorted bits.

Small organics - In this case, "organic" means "containing carbon-hydrogen bonds". The term has taken on a variety of other meanings in food, but we'll stick with the "C-H bonds" definition. These can include things like vitamins, metabolic products, and other bits & pieces.

BIG organics - Lipids, proteins, carbohydrates, DNA/RNA - These are all much bigger molecules.
Lipids - These are fats, mostly composed of triglycerides. The length and "saturation" of the long fatty acid chains in triglycerides define their properties. The longer and more saturated the chains are, the more effectively they can pack, meaning that they are often solids at room temperature. Unsaturation (double bonds) can put some "kinks" in these long chains that can significantly affect their properties.
Proteins - Proteins are polymers composed of amino acid monomers. The central carbon in an amino acid has an amine group (-NH₂), a carboxylic acid group (-COOH), a hydrogen (-H), and a 4th group that varies (the "sidechain"). The hydrophobicity of the sidechain determines the structure of a protein, and the structure of a protein determines the function of the protein. Proteins are the workhorses of biochemistry/biology.

We'll get to the others next week. Don't forget the quiz in D2L and enjoy your weekend.