Deep frying

Deep frying

Overview
Deep frying is a cooking
Cooking
Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...

 method in which food is submerged in hot oil
Cooking oil
Cooking oil is purified fat of plant origin, which is usually liquid at room temperature ....

 or fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

. This is normally performed with a deep fryer or chip pan
Chip pan
A chip pan is a deep-sided cooking pan used for deep-frying. Chip pans are named for their traditional use in frying chips ....

; industrially, a pressure fryer or vacuum fryer
Vacuum fryer
A vacuum fryer is a deep-frying device housed inside a vacuum chamber. It was originally developed for potato chip production.Vacuum fryers are fit to process low-quality potatoes that contain higher sugar levels than normal, as they frequently have to be processed in spring and early summer before...

 may be used.

Deep frying is classified as a dry cooking method because no water is used. Due to the high temperature involved and the high heat conduction of oil, it cooks food extremely quickly.


If performed properly, deep-frying does not make food excessively greasy, because the moisture
Moisture
Humidity is the amount of moisture the air can hold before it rains. Moisture refers to the presence of a liquid, especially water, often in trace amounts...

 in the food repels the oil.
Discussion
Ask a question about 'Deep frying'
Start a new discussion about 'Deep frying'
Answer questions from other users
Full Discussion Forum
 
Unanswered Questions
Recent Discussions
Encyclopedia
Deep frying is a cooking
Cooking
Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...

 method in which food is submerged in hot oil
Cooking oil
Cooking oil is purified fat of plant origin, which is usually liquid at room temperature ....

 or fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

. This is normally performed with a deep fryer or chip pan
Chip pan
A chip pan is a deep-sided cooking pan used for deep-frying. Chip pans are named for their traditional use in frying chips ....

; industrially, a pressure fryer or vacuum fryer
Vacuum fryer
A vacuum fryer is a deep-frying device housed inside a vacuum chamber. It was originally developed for potato chip production.Vacuum fryers are fit to process low-quality potatoes that contain higher sugar levels than normal, as they frequently have to be processed in spring and early summer before...

 may be used.

Deep frying is classified as a dry cooking method because no water is used. Due to the high temperature involved and the high heat conduction of oil, it cooks food extremely quickly.

Technique



If performed properly, deep-frying does not make food excessively greasy, because the moisture
Moisture
Humidity is the amount of moisture the air can hold before it rains. Moisture refers to the presence of a liquid, especially water, often in trace amounts...

 in the food repels the oil. The hot oil heats the water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 within the food, steaming
Steaming
Steaming is a method of cooking using steam. Steaming is considered a healthy cooking technique and capable of cooking almost all kinds of food.-Method:...

 it from the inside out; oil cannot go against the direction of this powerful flow because (due to its high temperature) the water vapor pushes the bubbles toward the surface. As long as the oil is hot enough and the food is not immersed in the oil for too long, oil penetration will be confined to the outer surface. However, if the food is cooked in the oil for too long, much of the water will be lost and the oil will begin to penetrate the food. The correct frying temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 depends on the thickness and type of food, but in most cases it lies between 175 and 190 °C (345–375 °F).

Oil deterioration


Overheating or over-using the frying oil leads to formation of rancid-tasting
Rancidification
Rancidification is the chemical decomposition of fats, oils and other lipids . When these processes occur in food, undesirable odors and flavors can result. In some cases, however, the flavors can be desirable . In processed meats, these flavors are collectively known as "warmed over flavor"...

 products of oxidation
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

, polymerization
Polymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

, and other deleterious, unintended or even toxic compounds such as acrylamide
Acrylamide
Acrylamide is a chemical compound with the chemical formula C3H5NO. Its IUPAC name is prop-2-enamide. It is a white odourless crystalline solid, soluble in water, ethanol, ether, and chloroform. Acrylamide is incompatible with acids, bases, oxidizing agents, iron, and iron salts...

 (from starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

y foods). Deep-frying under vacuum
Vacuum fryer
A vacuum fryer is a deep-frying device housed inside a vacuum chamber. It was originally developed for potato chip production.Vacuum fryers are fit to process low-quality potatoes that contain higher sugar levels than normal, as they frequently have to be processed in spring and early summer before...

 helps to significantly reduce acrylamide formation, but this process is not widely used in the food industry
Food industry
The food production is a complex, global collective of diverse businesses that together supply much of the food energy consumed by the world population...

 due to the high investment cost involved.

Some useful tests and indicators of excessive oil deterioration are the following:
  • Sensory: Darkening, smoke, foaming, thickening, rancid taste and unpleasant smell when heating.
  • Laboratory: Acidity, anisidine value, viscosity
    Viscosity
    Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

    , total polar
    Chemical polarity
    In chemistry, polarity refers to a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds. Molecular polarity is dependent on the difference in...

     compounds
    Chemical compound
    A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

    , polymeric triglycerides.


Instruments that indicate total polar compounds, currently the best single gauge of how deep-fried an object is, are available with sufficient accuracy for restaurant and industry use.

Disadvantages


Deep frying produces large amounts of waste oil, which must be properly disposed. Waste oil is increasingly being recycled into biodiesel
Biodiesel
Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....

.

Some deep fry shortening
Shortening
Shortening is any fat that is solid at room temperature and used to make crumbly pastry. The reason it is called shortening is because it prevents cross-linkage between gluten molecules. Cross linking is what causes doughs to be sticky. Seeing as cake is not meant to be sticky, shortening is used...

s contain trans fat
Trans fat
Trans fat is the common name for unsaturated fat with trans-isomer fatty acid. Because the term refers to the configuration of a double carbon-carbon bond, trans fats are sometimes monounsaturated or polyunsaturated, but never saturated....

.

Cooking oil is flammable, and fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

s may be caused by it igniting at too high a temperature. Attempts to extinguish an oil fire with water cause the water to flash into steam due to the high heat of the oil, in turn sending the burning oil in all directions and thus aggravating the fire. Instead, oil fires must be extinguished via fire extinguisher
Fire extinguisher
A fire extinguisher or extinguisher, flame entinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations...

 or by smothering. Other means of extinguishing an oil fire include application of dry powder (e.g., baking soda, salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

) or fire fighting foam. Most commercial deep fryers are equipped with automatic fire suppression system
Fire suppression system
Fire suppression systems are used in conjunction with smoke detectors and fire alarm systems to improve and increase public safety. Suppression systems are governed by the codes under the NFPA 13 handbook.-Types:...

s using foam.

See also



  • Banana chips
    Banana chips
    Banana chips are deep-fried and/or dried slices of bananas . They can be covered with sugar or honey and have a sweet taste, or they can be fried in oil and spices and have a salty and/or spicy taste. Variants of banana chips may be covered with chocolate instead...

  • Deep-fried Twinkie
  • Deep-fried Mars Bar
    Deep-fried Mars bar
    A deep-fried Mars bar is an ordinary Mars bar normally fried in a type of batter commonly used for deep-frying fish, sausages, and other battered products...

  • Deep-fried pizza
    Deep-fried pizza
    Deep-fried pizza is a dish available in many chip shops in Scotland. It originated in the late 1970s and typically consists of the cheapest of cash and carry pizzas, though a choice of "toppings" is often available, usually plain , mushroom or onion. Served as a "Pizza Supper" or single in whole...

  • Finger steaks
    Finger steaks
    Finger steaks consist of 2–3” long by 1/2" wide strips of steak , battered with a tempura-like batter, and deep-fried in oil. Typically they are served with French fries and a buttered piece of thick toast...

  • French fried potatoes
  • Fried pickle
    Fried pickle
    Fried pickles are a snack food found commonly in the American South. It is made by deep-frying a sliced battered dill pickle.Fried Dill Pickles were popularized by Bernell "Fatman" Austin in 1963 at the Duchess Drive In located in Atkins, Arkansas. The Fatman's Recipe is only known to his family...

    s
  • "Toasted" ravioli
    Toasted ravioli
    Toasted ravioli, or breaded deep-fried ravioli, is an appetizer created and popularized, according to common claims, in St. Louis, Missouri. Toasted ravioli can be found on the menus of many St...



External links