Pongamia oil is derived from the seeds of the ''

Millettia pinnata ''Millettia pinnata'' is a species of tree in the pea family, Fabaceae, native to eastern and tropical Asia, Australia, and Pacific islands. It is often known by the synonym '' Pongamia pinnata''. Its common names include Indian beech and Pongam ...

'' tree, which is native to tropical and temperate

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. ''Millettia pinnata'', also known as '' Pongamia pinnata'' or ''Pongamia glabra'', is common throughout Asia and thus has many different names in different languages, many of which have come to be used in English to describe the seed oil derived from ''M. pinnata''; ''Pongamia'' is often used as the generic name for the tree and is derived from the genus the tree was originally placed in. Other names for this oil include honge oil, kanuga oil, karanja oil, and pungai oil.

Cultivation

''Millettia pinnata'' is native to

South South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

. Known in various languages as Indian beech, pongam, karanja, honge, kanuga, pongu and naktamala, it is now grown all over the world. Typically the plant starts yielding pods from the fifth year on with the yields increasing each year until it stabilizes around the tenth year. Seeds are usually harvested in the spring, each seed weighing from about to . The yield per tree can range from about to more than depending on conditions, with an average of 1500-1700 seeds per kilogram. Historically the pods are removed from the trees by beating the branches with sticks and decorticated using mallets or stones. Research is ongoing into mechanical harvesting methods. The basic nutritional components of ''Millettia pinnata'' seeds may change depending on the season and maturity of the tree but in general are as follows:Factsheet from New crops at Purdue University
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Description

Pongamia oil is extracted from the seeds by expeller pressing, cold pressing, or

solvent extraction A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

. The oil is yellowish-orange to brown in color. It has a high content of

triglycerides A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...

, and its disagreeable taste and odor are due to bitter flavonoid constituents including karanjin, pongamol,

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

and karanjachromene. ''Millettia pinnata'' has a number of different varieties but little research has been published on the differences between them. This combined with variances in soil and weather can change the specific composition of Pongamia oil. Typically Pongamia oil is composed of the following

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...

s: The physical properties of crude pongamia oil are as follows:

Uses

Traditional

It has been used as

lamp oil Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...

, in

leather tanning Tanning is the process of treating skins and hides of animals to produce leather. A tannery is the place where the skins are processed. Tanning hide into leather involves a process which permanently alters the protein structure of skin, makin ...

, in

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are use ...

making, and as a lubricant for thousands of years. Its toxicity, as well as its color, bitter taste, and disagreeable odour, keep it from being used in cooking, but it does have uses in traditional medicine for treating skin disease and liver disease. It is used as a fish poison, as the metabolites karanjin and pongamol are both toxic to fish.

Biodiesel

Many studies have been done to convert pongamia oil into

biodiesel Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oil ...

. The following table shows the physical properties of the methyl esters of pongamia oil versus the ASTM D6751 and

EN 14214 EN 14214 is a standard published by the European Committee for Standardization that describes the requirements and test methods for FAME - the most common type of biodiesel. The technical definition of biodiesel is a fuel suitable for use in comp ...

biodiesel standards: The comparison of the

methyl ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s of pongamia oil to the ASTM D6751 standard for biodiesel fuels shows that processed pongamia oil is within the standards. Research has shown that

jatropha ''Jatropha'' is a genus of flowering plants in the spurge family, Euphorbiaceae. The name is derived from the Greek words ἰατρός (''iatros''), meaning "physician", and τροφή (''trophe''), meaning "nutrition", hence the common name ...

or pongamia oil can be mixed with palm oil to achieve an improved low-temperature

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

than pure palm oil and a higher oxidation stability than pure jatropha or pongamia oil. In addition, the methyl esters of pongamia oil have a cloud point of 19 °C, which is outside some country specific standards, and a pour point of 15 °C both of which would be problematic in lower temperature climates.

References