Cooking food means to heat it in order to make certain changes in it. skilled cooks know exactly what changes they want to make and what they have to do to get them right. to learn and master these cooking skills, it’s important for you to know why foods behave as they do when heated. For this, you have to study the theory.
Most of this section is devoted to understanding the results of applying heat to food. in addition, another basic concept of food science, that of emulsions, is discussed in detail.
This concept is important in the production of sauces and salad dressings, as well as various bakeshop preparations, such as cake batters. perhaps not all of this section will make sense to you at first.
But the ideas should become clearer to you after you think about them in relation to specific techniques, as demonstrated by your instructor.
Later in your studies, when you are learning about cooking meats, fish, vegetables, and making sauces and salad dressings, review this section from time to time. not only will you understand it better but also it should help you make more sense of the procedures you are learning and practicing.
- WHAT IS is HEAT?
Heat is a form of energy associated with atoms motion or molecules. When a substance absorb heat, its molecules move faster. liquids & gases, the molecules moves quickly from place to another & bounce off each other more frequently. In solids, the molecules mostly stay in place, but they vibrate with more energy.
Temperature is a measurement of this molecular activity. the higher the temperature, the faster the molecules moves.
When fast-moving molecules in hot substances come in contact with slower molecules in cold substances; fast molecules encounter slower ones and transfer some of their energy, making the slower molecules move faster, or heat up.
So heat is transferred, the hot substance loses energy and the colder substance gains energy. the moving molecules in a liquid, like water sometimes move to the surface with enough energy to break through & escape to become a gas. this is called: evaporation.
When the molecules in the liquid move faster, more of them will escape in a shorter time. this is why hot water evaporates more quicker than cold water.
If you add enough heat to foods, molecules may move so fast so the structure of the food changes. For example, sucrose (regular sugar) may break apart & forms new molecules that happen to have a brown color and the taste of caramel. or the protein molecules may break apart and reform with a different structure. Creating these molecular changes is called: cooking.