Pongamia oil is derived from the seeds of the Millettia pinnata tree, which is native to tropical and temperate Asia. 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.[1]

Other English names for this oil include Honge oil (from Kannada), Kanuga oil (from Telugu), Karanja oil (from Hindi), and Pungai oil (from Tamil).


Pods and seeds of Millettia pinnata

Millettia pinnata is native to South and Southeast Asia. Known in various languages as Indian beech, Pongam, Karanja, Honge, Kanuga, 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 1.1 grams (0.039 oz) to 1.8 grams (0.063 oz). The yield per tree can range from about 10 kilograms (22 lb) to more than 50 kilograms (110 lb) 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:[2]

Component Percentage
Oil 27% - 39%
Protein 17% - 37%
Starch 6% - 7%
Crude fiber 5% - 7%
Moisture 15% - 20%
Ash 2% - 3%


Pongamia oil is extracted from the seeds by expeller pressing, cold pressing, or solvent extraction. The oil is yellowish-orange to brown in color. It is toxic and will induce nausea and vomiting if eaten, but it is used in many traditional remedies.[citation needed] It has a high content of triglycerides, and its disagreeable taste and odor are due to bitter flavonoid constituents including karanjin, pongamol, tannin and karanjachromene.[2]

Millettia pinnata has a number of different varieties but little research has been published on the differences between them.[3] 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 acids:[2][4]

Fatty acid Nomenclature Percentage
Palmitic C16:0 3.7% – 7.9%
Stearic C18:0 2.4% – 8.9%
Oleic C18:1 44.5% – 71.3%
Linoleic C18:2 10.8% – 18.3%
Linolenic C18:3 2.6%
Arachidic C20:0 2.2% – 4.7%
Eicosenoic C20:1 9.5% – 12.4%
Behenic C22:0 4.2% – 5.3%
Lignoceric C24:0 1.1% – 3.5%

The physical properties of crude Pongamia oil are as follows:[4]

Property Unit Value
Acid value mg KOH/g 4.0 - 12
Calorific value kcal/kg 8742
Cetane number 42
Density g/cm3 0.924
Iodine value g/100 g 86.5 - 87
Saponification value mg KOH/g 184 - 187
Specific gravity 0.925
Unsaponifiable matter % w/w 2.6 - 2.9
Viscosity mm2/sec 40.2
Boiling point °C 316
Cloud point °C 3.5
Fire Point °C 230
Flash point °C 225
Pour point °C -3.0



It has been used as lamp oil, in leather tanning, in soap 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.[1]

There is also research indicating that the oil can be used as a natural insecticide.[5]

It also used as a fish poison, as the metabolites karanjin and pongamol are both toxic to fish.[6][7]

Feedstock for first and second generation Biodiesel

Fatty Acid Methyl Esters (FAME)

Many studies have been done to convert Pongamia oil into biodiesel. The following table shows the physical properties of the methyl esters of Pongamia oil versus the ASTM D6751 and EN 14214 biodiesel standards:

Property Unit Methyl esters ASTM D6751 EN 14214
Acid value mg KOH/g 0.46 - 0.5 <0.8 <0.5
Calorific value kcal/kg 3700
Cetane Number 41.7 - 56 >45 >51
Density at 15 °C g/cm3 0.86 - 0.88 0.87 - 0.89 0.86 - 0.90
Viscosity at 40 °C mm2/s 4.77 1.9 - 6.0 3.5 - 5.0
Iodine value g/100 g 86.5 - 91 <120
Oxidation Stability at 110 °C h 2.24 >6
Saponification value mg KOH/g 184 - 187
Unsaponifiable matter % w/w 2.6 - 2.9
Boiling point °C 316
Cloud point °C 19 0/-15 †
Fire Point °C 230
Flash point °C 174 >130 >101
Pour point °C 15
† This is not a property of the EN 14214 standard; it is country specific standard for summer/winter seasons.

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 to achieve an improved low-temperature viscosity 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.

Hydro-treated Vegetable Oil (HVO) or Renewable Diesel

Renewable Diesel is produced through hydrocracking of vegetable oils such as Pongamia.

Hydrocracking is a refinery method that uses elevated temperatures and pressure in the presence of a catalyst to break down larger molecules such as those found in vegetable oils, into shorter hydrocarbon chains used in diesel engines. Renewable Diesel is also called green diesel, or hydro-treated vegetable oil (HVO). Renewable Diesel is a true hydrocarbon just like diesel and meets ASTM International’s standard for Diesel Fuel Oils (D-975). Because of this structural difference, Renewable Diesel is a superior product with a higher cetane index than typical ultra-low sulfur diesel (ULSD), and unlike biodiesel, an energy density value equivalent to ULSD.

See also


  1. ^ a b "Pongamia Factsheet" (PDF). Retrieved 2013-10-02. 
  2. ^ a b c Factsheet from New crops at Purdue University
  3. ^ "Weed Risk Assessment : Pongamia" (PDF). Daff.qld.gov.au. Retrieved 2013-11-21. 
  4. ^ a b Ashok Pandey (2008). Handbook of Plant-Based Biofuels. CRC. pp. 255–266. ISBN 1-56022-175-5. 
  5. ^ Scott, Paul T.; Pregelj, Lisette; Chen, Ning; Hadler, Johanna S.; Djordjevic, Michael A.; Gresshoff, Peter M. (2008). "Pongamia pinnata: An Untapped Resource for the Biofuels Industry of the Future". BioEnergy Research. 1: 2. doi:10.1007/s12155-008-9003-0. 
  6. ^ Arole, SR (2010). "Pongamia pinnata L: A Comprehensive Review" (PDF). International Journal of PharmTech Research. 
  7. ^ S., Mahli, S.; P., Basu, S.; P., Sinha, K.; C., Banerjee, N. "Pharmacological effects of karanjin and pongamol [from seed oil of Pongamia pinnata]". www.cabdirect.org. Retrieved 2016-03-03.