2. Cooking Principles 18

3. Objective
Understand the reasons food is cooked.

4. What Is Cooking?
Soon after prehistoric man harnessed fire, cooking was possible
Foods are cooked for several reasons
Cooked food is safer to eat
Cooked food is more digestible
The texture, taste, aroma, and appearance of foods are improved

5. Objective
Explain what happens to food when it is cooked and overcooked.

6. What Happens to Foods When They Are Cooked?
Microorganisms are destroyed
Most bacteria, fungi, and molds are killed at temperatures above 135°F (57°C)
Connective tissue in meats breaks down
Most connective tissue becomes tender when it is properly cooked
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7. What Happens to Foods When They Are Cooked?
Proteins coagulate
Coagulation causes the texture of many foods to change when cooked
Fibers in vegetables break down
Heat breaks down vegetable fibers, making them tender and releasing certain nutrients
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8. What Happens to Foods When They Are Cooked?
Starches absorb liquid
When starches combine with hot liquid, gelatinization occurs
This process is used in many preparations in the kitchen and bakeshop
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9. What Happens to Foods When They Are Cooked?
Flavors blend and change
Flavors change during the caramelization of sugars
Amino acids in proteins change when heated, creating new flavors
Cooking helps to blend or marry the flavors of multiple ingredients

10. Effects of Overcooking
When foods are cooked to excessive temperatures or for too long, the following problems may occur:
Foods become mushy and disintegrate or tough and stringy
Proteins can curdle or toughen
Moisture is lost and foods become dry
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11. Effects of Overcooking
Sugars burn, causing a bitter taste
Green vegetables lose their color and turn brown
Nutrients are lost or destroyed

12. Objective
Classify various methods of cooking by the process of heat transfer.

13. Methods of Heat Transfer
Different appliances and utensils transfer heat in different manners
Understanding the methods of heat transfer is key to distinguishing between different cooking methods

14. Conduction
During conduction, heat energy travels through solid substances from one molecule to adjacent molecules by means of the vibration of electrons
Heat is conducted through the heating element through pots and pans to the food

15. Convection
Natural convection occurs when warm air rises to the top of an oven or when warmer liquid rises to the top of a pot
The cooler air or liquid descends to the bottom and creates a circular flow
Mechanical circulation of the gas or liquid speeds up the transfer of heat

16. Radiation Radiation does not require a conductor
The flames of a broiler transfer heat to food by means of radiation
In microwave cooking, microwaves pass through the food causing the water molecules to heat

17. Objective
Explain basic cooking methods.

18. Cooking Methods Cooking methods can be classified as dry-heat methods
moist-heat methods
combination methods

19. Dry-Heat Methods
Dry-heat methods use higher temperatures than moist-heat methods
Because dry heat does
not break down fibers or tissues as well as moist heat, this method is most often used with tender products
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20. Dry-Heat Methods Sautéing
Requires only enough fat to coat the bottom of the pan
Stir-frying is similar to sautéing
Sweating is often used with onions, mirepoix, and garlic
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21. Dry-Heat Methods Panfrying
Food is turned during the cooking process to cook both sides evenly
Large or thick pieces of meat, fish, or poultry may be panfried and then finished in the oven
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22. Dry-Heat Methods Deep frying
Most foods are coated with flour, breading, or batter before being fried
Best done in a deep-fat fryer, not on the stovetop
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23. Dry-Heat Methods Grilling
Foods can be grilled over gas flames, electric burners, charcoal, or hard woods
Juices dripping from the food into the heat source create smoke, which adds flavor
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24. Dry-Heat Methods Broiling Either a broiler or an oven
Heat source is above the food and is usually intense in order to sear or brown the food
Either a broiler or an oven
can be used to gratiner (grah tehn AY) a food product
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25. Dry-Heat Methods Roasting Most roasting is done in the oven
Food is uncovered so any moisture released can evaporate
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26. Dry-Heat Methods Baking
Foods are often baked covered to keep the moisture in the product
Products that require a gentle heat are baked in a water bath

27. Moist-Heat Methods
Moist-heat methods use liquid or steam in the cooking process
Moisture is an excellent conductor of heat
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28. Moist-Heat Methods Poaching Used for delicate food products
Liquid is often flavored
Shallow poaching: cooking liquid usually covers food less than halfway
Deep poaching: liquid fully covers the food
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29. Moist-Heat Methods Simmering
Used to make stocks and broths as well as to cook tough cuts of meat and poultry
Simmering is hot enough to
break down connective tissue, but not so hot that proteins become tough and cooking liquid cloudy
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30. Moist-Heat Methods Boiling
Used most often for vegetables, starches, and grains
Should not be used for meats, poultry, or eggs, because the higher temperature makes them tough
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31. Moist-Heat Methods Steaming
Temperature of steam is hotter than boiling water
Steam vapor rises and surrounds the product
Some steamers use a fan to create a more rapid convection

32. Combination Methods
Combination cooking methods apply both dry- and moist-heat techniques to the same food
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33. Combination Methods Braising Combines browning and simmering
Tenderizes tough products like simmering and has the
richer flavor and color of sautéed items
The cooking liquid from a braised dish is often used to make a sauce
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34. Combination Methods Stewing
Either the braising or simmering technique can be used to make a stew
Ingredients are cut in smaller pieces for stewing method

35. Review Explain why food is cooked.
Cooked food is safer to eat, is more digestible, and has improved texture, taste, aroma, and appearance
continued

36. Review Describe what happens when foods are cooked.
Microorganisms are destroyed
Connective tissue in meats breaks down
Proteins coagulate
Fibers in vegetables break down
Starches absorb liquid
Flavors blend and change
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37. Review Explain the three methods of heat transfer.
Conduction: the transfer of heat energy from one object to another through direct contact
Convection: the manner in which heat energy travels through liquids and gases
Radiation: the transfer of heat energy through waves
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38. Review Name the dry-heat cooking methods. Sautéing Panfrying
Deep frying
Grilling
Broiling
Roasting
Baking
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39. Review Name the moist-heat cooking methods. Poaching Simmering Boiling
Steaming
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40. Review
Name the combination cooking methods.
Braising
Stewing