Overview

Cooking is just edible chemistry. When you sear a steak, bake bread, or ferment beer, you are doing complex chemical reactions. Food Chemistry explains why toast tastes better than bread, why apples turn brown, and how to keep milk from spoiling.

Core Idea

The core idea is Transformation. We take raw biological materials (muscle, root, seed) and use heat, acid, or enzymes to change their texture and flavor to make them safe and delicious.

Formal Definition

The study of the chemical composition and properties of food and the chemical changes it undergoes.

Intuition

  • Chef: “Add lemon juice to the fish to make it taste bright.”
  • Chemist: “Add Citric Acid to denature the amines (fishy smell) and turn them into non-volatile salts.”

Examples

  • Maillard Reaction: The Holy Grail of cooking. When amino acids (protein) and sugars react at high heat (>140°C). It creates the brown crust on steak, the golden color of toast, and the flavor of roasted coffee. It is the “flavor reaction.”
  • Caramelization: The oxidation of sugar. It makes onions sweet and brown.
  • Emulsions: Mayonnaise. Mixing oil and water using a protein (egg yolk) to stabilize the interface. If you whisk too hard or get it too hot, the emulsion breaks (curdles).

Common Misconceptions

  • Chemicals in food are bad: “Chemical-free food” is a vacuum. Water is a chemical. An apple contains formaldehyde, cyanide, and acetone naturally. The dose makes the poison.
  • Searing seals in juices: False. Searing creates flavor (Maillard), but it actually squeezes out moisture.
  • Preservation: Stopping chemistry. Freezing slows reactions. Salting removes water (osmosis) so bacteria can’t grow. Pickling adds acid to kill microbes.
  • Molecular Gastronomy: Using lab tools (liquid nitrogen, alginate spheres) to create new textures in high-end restaurants.

Applications

  • Artificial Sweeteners: Molecules that trigger the “sweet” receptor on your tongue but can’t be digested, so they have zero calories.
  • Decaf Coffee: Using chemistry to extract one specific molecule (caffeine) while leaving the 1,000 flavor molecules behind.

Criticism / Limitations

  • Ultra-Processed Food: We have become too good at chemistry. We can make “food” that is perfectly engineered to be addictive (Doritos) but has no nutritional value.

Further Reading

  • McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. (The bible of food science).
  • Potter, Jeff. Cooking for Geeks.