Pongamia oil is derived from the seeds of the ''

Millettia pinnata ''Pongamia pinnata'' is a species of tree in the pea family, Fabaceae, native to eastern and tropical Asia, Australia, and the Pacific islands. It is the sole species in genus ''Pongamia''. It is often known by the synonym ''Millettia pinnata''. ...

'' tree, which is native to tropical and temperate

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. ''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 west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. 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
/ref>

Description

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

solvent extraction A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a gas ...

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

triglycerides A triglyceride (from ''wikt:tri-#Prefix, tri-'' and ''glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and oth ...

, and its disagreeable taste and odor are due to bitter

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

constituents including karanjin, pongamol,

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and Precipitation (chemistry), precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' is widel ...

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, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an ...

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

Uses

Traditional

It has been used as lamp oil, in leather tanning, in

soap Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...

making, and as a

lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...

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 renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats. The roots of bi ...

. The following table shows the physical properties of the methyl esters of pongamia oil versus the ASTM D6751 and EN 14214 biodiesel standards: The comparison of the methyl esters 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 or pongamia oil can be mixed with

palm oil Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of oil palms. The oil is used in food manufacturing, in beauty products, and as biofuel. Palm oil accounted for about 36% of global oils produced from o ...

to achieve an improved low-temperature

viscosity Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e ...

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