Cooking is the process of preparing food by applying heat, selecting, measuring and combining of ingredients in an ordered procedure for producing safe and edible food. The process encompasses a vast range of methods, tools and combinations of ingredients to alter the flavor or digestibility of food. Factors affecting the final outcome include the variability of ingredients, ambient conditions, tools, and the skill of the individual doing the actual cooking.

The diversity of cooking worldwide is a reflection of the aesthetic, agricultural, economic, cultural, social and religious diversity throughout the nations, races, creeds and tribes across the globe.

Applying heat to a food usually, though not always, chemically transforms it, thus changing its flavor, texture, consistency, appearance, and nutritional properties. Methods of cooking that involve the boiling of liquid in a receptacle have been practised at least since the 10th millennium BC, with the introduction of pottery.^{[citation needed]}

Contents 1 Effects of cooking 2 Nutrients 2.1 Proteins 2.2 Liquids 2.3 Fat 2.4 Carbohydrates 3 Cooking methods 4 Food safety 5 Disadvantages of cooking 6 Science of cooking 7 History of cooking 8 See also 9 References 10 External links

[edit] Effects of cooking

Cooking prevents many foodborne illnesses that would otherwise occur if the raw food was eaten. Also, cooking increases the digestibility of some foods such as grains. But in most cases if not cooked properly food can lose its flavor as well as its nutrients.

[edit] Nutrients

[edit] Proteins

Edible animal material, including muscle, offal, milk and egg white, contains substantial amounts of protein. Almost all vegetable matter (in particular legumes and seeds) also includes proteins, although generally in smaller amounts, by weight.

These foods may also be a source of essential amino acids. When proteins are heated they become de-natured and change texture. In many cases, this causes the structure of the material to become softer or more friable - meat becomes cooked. In some cases, proteins can form more rigid structures, such as the coagulation of albumen in egg whites. The formation of a relatively rigid but flexible matrix from egg white provides an important component of much cake cookery, and also underpins many desserts based on meringue.

[edit] Liquids

Cooking often involves water which is frequently present as other liquids, both added in order to immerse the substances being cooked (typically water, stock or wine), and released from the foods themselves. Liquids are so important to cooking that the name of the cooking method used may be based on how the liquid is combined with the food, as in steaming, simmering, boiling, braising and blanching. Heating liquid in an open container results in rapidly increased evaporation, which concentrates the remaining flavor and ingredients - this is a critical component of both stewing and sauce making.

[edit] Fat

Fats and oils come from both animal and plant sources. In cooking, fats provide tastes and textures. When used as the principal cooking medium (rather than water), they also allow the cook access to a wide range of cooking temperatures. Common oil-cooking techniques include sauteing, stir-frying, and deep-frying. Commonly used fats and oils include butter; olive oil; vegetable oils such as sunflower oil, corn oil, and safflower oil; animal fats such as lard, schmaltz, and beef fat (both dripping and tallow); and seed oils such as rapeseed oil (Canola or mustard oil), sesame oil, soybean oil, and peanut oil. The inclusion of fats tends to add flavour to cooked food, even though the taste of the oil on its own is often unpleasant. This fact has encouraged the popularity of high fat foods, many of which are classified as junk food.

[edit] Carbohydrates

Carbohydrates include simple sugars such as glucose (from table sugar) and fructose (from fruit), and starches from sources such as cereal flour, rice, arrowroot, potato. The interaction of heat and carbohydrate is complex.

Long-chain sugars such as starch tend to break down into more simple sugars when cooked, while simple sugars can form syrups. If sugars are heated so that all water of crystallisation is driven off, then caramelisation starts, with the sugar undergoing thermal decomposition with the formation of carbon, and other breakdown products producing caramel. Similarly, the heating of sugars and proteins elicits the Maillard reaction, a basic flavor-enhancing technique.

An emulsion of starch with fat or water can, when gently heated, provide thickening to the dish being cooked. In European cooking, a mixture of butter and flour called a roux is used to thicken liquids to make stews or sauces. In Asian cooking, a similar effect is obtained from a mixture of rice or corn starch and water. These techniques rely on the properties of starches to create simpler mucilaginous saccharides during cooking, which causes the familiar thickening of sauces. This thickening will break down, however, under additional heat.

Eating complex carbohydrates, such as whole wheat bread and pasta is more beneficial than eating simple carbs, such as white bread and muffins, mainly because they take longer to break down, keeping your energy levels elevated longer and keeping you from getting hungry as fast.

[edit] Cooking methods

Please help improve this section by expanding it. Further information might be found on the talk page. (September 2008)

For various cooking methods, see Category:Cooking techniques.

[edit] Food safety

Main article: Food safety

If heat is used in the preparation of food, this can kill or inactivate potentially harmful organisms including bacteria and viruses. The effect will depend on temperature, cooking time, and technique used. The temperature range from 41°F to 135°F (5°C to 57°C) is the "food danger zone." Between these temperatures bacteria can grow rapidly. Under optimal conditions, E. coli, for example, can double in number every twenty minutes. The food may not appear any different or spoiled but can be harmful to anyone who eats it. Meat, poultry, dairy products, and other prepared food must be kept outside of the "food danger zone" to remain safe to eat. Refrigeration and freezing do not kill bacteria, but only slow their growth. When cooling hot food, it should not be left standing or in a blast chiller (an appliance used to quickly cool food) for more than 90 minutes.

Cutting boards are a potential breeding ground for bacteria, and can be quite hazardous unless safety precautions are taken. Plastic cutting boards are less porous than wood and have conventionally been assumed to be far less likely to harbor bacteria.^[1] This has been debated, and some research have shown wooden boards are far better.^[2] Washing and sanitizing cutting boards is highly recommended, especially after use with raw meat, poultry, or seafood. Hot water and soap followed by a rinse with an antibacterial cleaner (dilute bleach is common in a mixture of 1 tablespoon per gallon of water, as at that dilution it is considered food safe, though some professionals choose not to use this method because they believe it could taint some foods), or a trip through a dishwasher with a "sanitize" cycle, are effective methods for reducing the risk of illness due to contaminated cooking implements.^[2]

[edit] Disadvantages of cooking

See also: Carcinogens#Carcinogens in prepared food and Raw foodism

Cooking food increases the risk of some of detrimental effects on food or health or both.

Cooking of vegetables and fruit containing vitamin c both elutes the vitamin into the cooking water and degrades the vitamin through oxidation. The reduction can be very significant with extended cooking.

Peeling vegetables can also substantially reduce the vitamin C content , especially in the case of potatoes where most vitamin C is in the skin.

Baking, grilling or broiling food , especially starchy foods, until a toasted crust is formed generates significant concentrations of acrylamide, a known carcinogen.

Cooking dairy products may reduce a protective effect against colon cancer. Researchers at the University of Toronto suggest that ingesting uncooked or unpasteurized dairy products (see also Raw milk) may reduce the risk of colon cancer. Mice and rats fed uncooked sucrose, casein, and beef tallow had one-third to one-fifth the incidence of microadenomas as the mice and rats fed the same ingredients cooked.^[3][4]

Several studies published since 1990 indicate that cooking muscle meat creates heterocyclic amines (HCAs), which are thought to increase cancer risk in humans. Researchers at the National Cancer Institute found that human subjects who ate beef rare or medium-rare had less than one third the risk of stomach cancer than those who ate beef medium-well or well-done.^[5] While eating muscle meat raw may be the only way to avoid HCAs fully, the National Cancer Institute states that cooking meat below 212 °F (100 °C) creates "negligible amounts" of HCAs. Also, microwaving meat before cooking may reduce HCAs by 90%.^[6] Nitrosamines, present in processed and cooked foods, have also been noted as being carcinogenic, being linked to colon cancer.

Also, toxic compounds called PAHs, or Polycyclic aromatic hydrocarbons, present in processed, smoked and cooked foods, are known to be carcinogenic.^[7] German research in 2003 showed significant benefits in reducing breast cancer risk when large amounts of raw vegetable matter are included in the diet. The authors attribute some of this effect to heat-labile phytonutrients.^[8]

Heating sugars with proteins or fats can produce Advanced glycation end products ("glycotoxins").^[9]

[edit] Science of cooking

The application of scientific knowledge to cooking and gastronomy has become known as molecular gastronomy. This is a subdiscipline of food science. Important contributions have been made by scientists, chefs and authors such as Herve This (chemist), Nicholas Kurti (physicist), Peter Barham (physicist), Harold McGee (author), Shirley Corriher (biochemist, author), Heston Blumenthal (chef), Ferran Adria (chef), Robert Wolke (chemist, author) and Pierre Gagnaire (chef).

[edit] History of cooking

There is, as yet, no clear evidence as to when cooking was invented. Richard Wrangham argues that cooking was invented as far back as 1.8 million to 2.3 million years ago. Other researchers believe that cooking was invented as late as 40,000 or 10,000 years ago. Evidence of fire is inconclusive as wildfires started by lightning-strikes are still common in East Africa and other wild areas, and it is difficult to determine as to when fire was used for cooking, as opposed to just being used for warmth or for keeping predators away. Most anthropologists contend that cooking fires began in earnest barely 250,000 years ago, when ancient hearths, earth ovens, burnt animal bones, and flint appear across Europe and the middle East. Back 2 million years ago, the only sign of fire is burnt earth with human remains, which most anthropologists consider coincidence rather than evidence of intentional fire.^[10]

[edit] See also

Main list: Topic outline of cooking

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