Effects of heat on foods

Basic cooking principles

Effects of heat on foods

Food are composed of  proteins ,fats , carbohydrates and water , lus small amounts of others compounds such as minerals (including salt) ,vitamins <pigments (coloring angents), and flavor elements. It is important to understand how these components react when heated or mixed with other foods. You will then be better equipped to correct cooking faults when they occur and to anticipate the effects  of changing cooking menthods <cooking temeratures<or ingredient proportions.

In other words, when you know why foods behave as they do ,you can then understand how to get them to behave as yopu want them to .



1.                  protein is a major component of meats , poultry,fish, eggs,milk , and milk products.it is present in smaller amounts in nuts,beans, and grains .

2.                   coagulation. As proteins are heated,they become firm or coagulate. As the temperature increases,they shrink,become firmer and lose more moisture. Exposure of proteins to excessive heat toughens them and makes them dry. Most proteins complete coagulation or are cooked At 160 to 185 F

3.                  connective  tissues are special proteins that are present in meats .meats with a great deal of connective tissue are tough, but some connective tissues are dissolved when ciiked slowly with moisture .by cooking tough meats properly,therefore,they can be made more tender .these techniques are explained in >>>>>>>>……

4.                  acids, such as lemon juice, vinegar , and tomato products , do two things to proteins:

a          they speed coagulation.

b          they help dissolve some   connective tissues.


1.         starches and sugars are both compounds are present in foods in many different form .they            are found in fruits vegetables ,grains,beans        and      nuts , meat and fish also contain a      very small        amount of carbohydrate.

2.         for the cook the two most important changes           in carbohydrates caused by heat are   caramelization and  gelatinization :

a.         caramelization is the browning of    sugars. The browning of seared meats and sautéed vegetables and the golden  color of bread crust are form of   caramelization.

b.         gelatinization occurs when starches  absorb water and swell . this is a major principle in the thickening of sauces and  in the production of breads and pastries

acids inhibit gelatinization. A sauces  thick ened with flour or starch will be  thinner if it contains acaid .

fruit and vegetable fiber

1.                  fiber is the name for a group of complex substances that give structure and firmness to plant.this fiber cannot be digested

2.                  the softening of fruits and vegetables in cooking is in part the breaking down of fiber.

3.                  sugar makes fiber more firm. Fruit cooked with sugar keeps its shape better than fruit cooked without sugar.

4.                  baking soda make fiber softer. Vegetables should not be cooked with baking soda because they become mushy and vitamins



  1. fats are present in meats poultry ,fish , eggs , milk products ,nuts and whole grains , and to a lesser extent ,in vegetables and fruit .fat are also important as cooking medium as for frying.
  2. fats can be either solid or liquid at room temperature liquid fats are called oils. Melting points of solid fats vary
  3. when fats are heated, they begin to break donw.when hot enough.they deteriorate rapidly and begin to smoke. The temperature at which this happens is called  the smoke point, and it vbaries for different fats. A stable fat –one with a high smoke point- is an important consideration in deep-fat frying.


Minerals,vitamins ,pigments,flavor components

  1. minerals and vitamins are important to the nutritional quality of the food .pigments and flavor components are important to a foood`s appearance and teste and may determine whether the food is appetizing enough to eat. So it is important to preserve all these elements.
  2. all og these components may be leached out, or dissolved away,from foods during cooking
  3. vitamints and pigments may also be destroyed by heat,by long cooking and by other elements present during cooking
  4. It is important then .to select cooking methods  that preserve ,as much as possible ,a food`s nutrients  and appearance .this will always be a consideration when cooking techiques are explained in the remainder of this web .

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