Cooking is chemistry you can see, smell, and taste. Heat changes the structure of food molecules, turning raw ingredients into meals with new textures, colors, aromas, and flavors. These changes matter because they affect nutrition, food safety, and how our bodies digest food.
Understanding cooking science helps students make healthier choices and follow recipes more accurately.
In a hot pan or pot, proteins unfold, starches absorb water, sugars brown, fats melt, and water evaporates into steam. Reactions such as the Maillard reaction create the browned flavor on toast, roasted vegetables, and seared meat. Temperature, time, water, acidity, and surface area all control how fast these changes happen.
Food science connects chemistry, biology, and health by showing how molecules become energy and nutrients for the body.
Key Facts
- Energy from food is measured in calories or kilocalories: 1 Calorie = 1 kilocalorie = 1000 calories.
- Heat transfer in cooking occurs by conduction, convection, and radiation.
- Specific heat equation: q = mcΔT, where q is heat energy, m is mass, c is specific heat, and ΔT is temperature change.
- Proteins denature when heat or acid changes their shape, which can make eggs firm and meat more solid.
- The Maillard reaction occurs when amino acids and reducing sugars react during heating, often above about 140°C.
- Water boils at 100°C at standard pressure, and steam carries energy away as water evaporates.
Vocabulary
- Denaturation
- Denaturation is the change in a protein's shape caused by heat, acid, salt, or mixing.
- Maillard Reaction
- The Maillard reaction is a browning reaction between amino acids and sugars that creates many cooked flavors and aromas.
- Caramelization
- Caramelization is the browning and flavor change that happens when sugars are heated enough to break down.
- Emulsion
- An emulsion is a mixture of two liquids that normally do not mix, such as oil and water in salad dressing.
- Gelatinization
- Gelatinization is the process in which starch granules absorb water and swell when heated, thickening foods like sauces and pudding.
Common Mistakes to Avoid
- Using only cooking time instead of temperature is a mistake because food safety and texture depend on the internal temperature, not just how long food has been heated.
- Assuming all browning is burning is a mistake because controlled browning can be the Maillard reaction or caramelization, which create desirable flavor before charring begins.
- Adding oil and water without mixing or an emulsifier is a mistake because oil is nonpolar and water is polar, so they separate unless droplets are dispersed and stabilized.
- Cooking vegetables for too long is a mistake because excessive heat and water can break down texture, color, and some heat-sensitive nutrients.
Practice Questions
- 1 A 250 g pot of soup has a specific heat of about 4.0 J/g°C. How much heat is needed to raise its temperature from 20°C to 80°C?
- 2 A snack contains 8 g of protein, 10 g of carbohydrate, and 6 g of fat. Using 4 Calories per gram for protein, 4 Calories per gram for carbohydrate, and 9 Calories per gram for fat, how many Calories are in the snack?
- 3 Two identical potato slices are cooked, but one is cut into thin strips and the other is left as a thick slice. Explain which cooks faster and why, using heat transfer and surface area.