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Rancidification

 

 
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Rancidification
 
 
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Rancidification is the decomposition of fat
Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
s, oil
Oil

An oil is a chemical substance that is in a viscosity liquid state at room temperature or slightly warmer, and is both hydrophobic and lipophilic ....
s and other lipid
Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
s by hydrolysis
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
 or oxidation, or both. Hydrolysis will split fatty acid
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
 chains away from the glycerol
Glycerol

Glycerol is a chemical compound also commonly called glycerin or glycerine. It is a colorless, odorless, Viscosity liquid that is widely used in pharmaceutical formulations....
 backbone in glyceride
Glyceride

Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids.Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides....
s. These free fatty acids can then undergo further auto-oxidation
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
. Oxidation primarily occurs with unsaturated fat
Unsaturated fat

An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. A fat molecule is Monounsaturated fat if it contains one double bond, and polyunsaturated if it contains more than one double bond....
s by a free radical-mediated process. These chemical processes can generate highly reactive molecules in rancid foods and oils, which are responsible for producing unpleasant and noxious odors and flavors.






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Rancidification is the decomposition of fat
Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
s, oil
Oil

An oil is a chemical substance that is in a viscosity liquid state at room temperature or slightly warmer, and is both hydrophobic and lipophilic ....
s and other lipid
Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
s by hydrolysis
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
 or oxidation, or both. Hydrolysis will split fatty acid
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
 chains away from the glycerol
Glycerol

Glycerol is a chemical compound also commonly called glycerin or glycerine. It is a colorless, odorless, Viscosity liquid that is widely used in pharmaceutical formulations....
 backbone in glyceride
Glyceride

Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids.Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides....
s. These free fatty acids can then undergo further auto-oxidation
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
. Oxidation primarily occurs with unsaturated fat
Unsaturated fat

An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. A fat molecule is Monounsaturated fat if it contains one double bond, and polyunsaturated if it contains more than one double bond....
s by a free radical-mediated process. These chemical processes can generate highly reactive molecules in rancid foods and oils, which are responsible for producing unpleasant and noxious odors and flavors. These chemical processes may also destroy nutrient
Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment....
s in food. Under some conditions, rancidity, and the destruction of vitamin
Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
s, occurs very quickly.

Antioxidant
Antioxidant

An antioxidant is a molecule capable of slowing or preventing the Redox of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent....
s are often added to fat-containing foods in order to retard the development of rancidity due to oxidation. Natural anti-oxidants include flavonoid
Flavonoid

The term flavonoid refers to a class of plant secondary metabolites. According to the IUPAC nomenclature, they can be classified into:*flavonoids, derived from 2-phenylchromone structure...
s, polyphenol
Polyphenol

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule....
s, ascorbic acid
Ascorbic acid

Ascorbic acid is a sugar acid with antioxidant properties. Its appearance is white to light-yellow crystals or powder. It is water-soluble. The L-enantiomer of ascorbic acid is commonly known as vitamin C....
 (vitamin C) and tocopherol
Tocopherol

Tocopherol, a class of chemical compounds of which many have vitamin E activity, describes a series of organic compounds consisting of various methylated phenols....
s (vitamin E). Synthetic antioxidants include butylated hydroxyanisole
Butylated hydroxyanisole

E320 redirects here. For the automobile, see Mercedes-Benz E-Class.Butylated hydroxyanisole is an antioxidant consisting of a mixture of two isomeric organic compounds, 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole....
 (BHA), butylated hydroxytoluene
Butylated hydroxytoluene

Butylated hydroxytoluene , also known as butylhydroxytoluene, is a lipophilic organic compound that is primarily used as an antioxidant food additive as well as in cosmetics, pharmaceuticals, jet fuels, rubber, petroleum products, Transformer oil, and embalming fluid....
 (BHT), propyl 3,4,5-trihydroxybenzoate also known as propyl gallate
Propyl gallate

Propyl gallate, or propyl 3,4,5-trihydroxybenzoate is an ester formed by the condensation of gallic acid and Propan-1-ol. It is an antioxidant added to foods containing oils and fats to prevent oxidation....
 and ethoxyquin
Ethoxyquin

Ethoxyquin is a quinoline-based antioxidant used as a food preservative and a pesticide . It is commonly used as a preservative in pet foods to prevent the rancidification of fats....
. The natural antioxidants tend to be short-lived, so synthetic antioxidants are used when a longer shelf-life is preferred. The effectiveness of water-soluble antioxidants is limited in preventing direct oxidation within fats, but is valuable in intercepting free-radical
Radical (chemistry)

In chemistry, radicals are atoms, molecules or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly chemical reaction, so radicals are likely to take part in chemical reactions....
s that travel through the watery parts of foods. A combination of water-soluble and fat-soluble antioxidants is ideal, usually in the ratio of fat to water.

In addition, rancidification can be decreased, but not completely eliminated, by storing fats and oils in a cool, dark place with little exposure to oxygen or free-radicals, since heat and light accelerate the rate of reaction of fats with oxygen.

See also

  • Food preservation
    Food preservation

    Food preservation is the process of treating and handling food to stop or greatly slow down spoilage caused or accelerated by micro-organisms....
  • Preservative
    Preservative

    A preservative is a natural or synthetic chemical compound that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc....
  • Putrefaction
    Putrefaction

    Putrefaction is the decomposition of animal proteins, especially by Anaerobic organism, described as putrefying bacteria. Decomposition is a more general process....
  • Fermentation
    Fermentation (food)

    Fermentation in food processing typically refers to the conversion of sugar to alcohol using yeast under anaerobic conditions. A more general definition of fermentation is the chemical conversion of carbohydrates into alcohols or acids....