Stillingia oil is an

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

extracted (by

solvent 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 ...

s) from the seeds of plants of the ''

Triadica ''Triadica'' is a plant genus of the family Euphorbiaceae first described as a genus in 1790. It is native to eastern southeastern, and southern Asia. Species included are: # '' Triadica cochinchinensis'' Lour. - China (Anhui, Fujian, Guangdong, ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

such as ''

Triadica sebifera ''Triadica sebifera'' is a tree native to eastern China. It is commonly called Chinese tallow, Chinese tallowtree, Florida aspen, chicken tree, gray popcorn tree, or candleberry tree. The seeds (as well as from those of '' Triadica cochinchinen ...

'' (Chinese tallow tree) and ''

Triadica cochinchinensis ''Triadica cochinchinensis'' is a species of tree known as the mountain tallow tree. The seeds (as well as from those of '' Triadica sebifera'') are the sources of stillingia oil, a drying oil A drying oil is an oil that hardens to a tough, ...

'' (Mountain tallow tree). It is a

drying oil A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (no ...

used in

paints Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...

and varnishes, and it is believed to be toxic in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. It must be distinguished from stillingia tallow, a fatty substance that surround the seeds in the fruit and must be removed before extracting the oil. The name of the oil was given when the two plants were classified in the genus ''

Stillingia ''Stillingia'' is a plant genus of the family Euphorbiaceae, first described for modern science as a genus in 1767. The genus is native to Latin America, the southern United States, and various islands in the Pacific and Indian Oceans. Toothleaf ...

'', with

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

s "''Stillingia sebifera''" and "''Stillingia discolor''". Sometime prior to 1950 the species were reclassified in the genus ''

Sapium ''Sapium'' is a genus of flowering plants in the family Euphorbiaceae. It is widespread across most of Latin America and the West Indies. Many Old World species were formerly included in the genus, but recent authors have redistributed all the O ...

'', and articles from the 1950s still use the names "''Sapium sebiferum''" and "''Sapium discolor''" However, since about 2002 the plants have been reclassified again in the genus ''

'', and the second one had its species name changed to "''cochinchinensis''". Stillingia oil has a typical drying time of 4–6 hours. The seeds produce 20-30% w/w of tallow fat and 10-17% w/w of stillingia oil. It has

iodine number Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vio ...

127, a

saponification Saponification is a process of converting esters into soaps and alcohols by the action of aqueous alkali (for example, aqueous sodium hydroxide solutions). Soaps are salts of fatty acids, which in turn are carboxylic acids with long carbon chains. ...

value of 206, and a thiocyanogen value of 100.7.

Composition

The composition of the oil may vary considerably with the age of the seeds (which can remain on the tree for a year after maturation) and with the extraction process. The major components of typical fresh oil are

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 ...

of the following fatty acids: (a) Fatty acid codes used in the discussion below.
(b) Molar percentages.
Several analyses of authentic oil in the 1950s found significant amounts of 2.4-decadienoic acid, later identified as the ''trans''-2, ''cis''-4 isomer, which had not been detected in natural oils before, and was conjectured to play a relatively prominent part in the drying and

polymerizing In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many for ...

properties of stillingia oil. Another analysis (1992) found that the

tocopherol Tocopherols (; TCP) are a class of organic chemical compounds (more precisely, various methylated phenols), many of which have vitamin E activity. Because the vitamin activity was first identified in 1936 from a dietary fertility factor in rat ...

fraction contains nearly pure (92%) γ-tocotrienol. According to a 1953 analysis of authentic oil, 64% (by mass) of the oil's triglycerides have three unsaturated

acyl In chemistry, an acyl group is a moiety derived by the removal of one or more hydroxyl groups from an oxoacid, including inorganic acids. It contains a double-bonded oxygen atom and an alkyl group (). In organic chemistry, the acyl group (IUPAC ...

s connected to the

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

hub, 34% have two, and about 2% have just one. The most common triglyceride component, with over half the mass, had (1) one linoleic and two linolenic acyls, or LNN or NLN using the codes of the table above. The next two most common types have a 2,4-decadienoic acyl on the second carbon of the

hub, flanked by (2) one linoleic and one linolenic acyl (LDN), or (3) two linolenic acyls (NDN). The 2,4-decadienoic acyl occurs almost exclusively in those two components. There are smaller proportions of triglycerides with (4) one saturated, one linoleic, and one linolenic (XLN, LXN, etc.); (5) one saturated and two linolenic; (XNN or NXN) (6) one oleic, one linoleic, one linolenic (OLN, LON, etc.); and (7) one oleic and two linolenic (ONN o NON). Over 95% of the triglycerides in stillingia oil were found to have three doubly-unsaturated fatty acids. This proportion is greater than that of

linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...

, and comparable with that in conophor oil. An analysis in 1992 found that an 8-hydroxy-5,6-octadienoic acid was joined to by an estolide linkage to the 2,4-decadienoic acyl. A more recent analysis (2009) of commercial oil found instead 80% (molar) of LLN, 14% PLN, 3% PPL, 1.5 RPL, and 0.5 SLN. This analysis also failed to find the 2,4-decadienoic acid. Instead it found twice as much oleic acid (16%), 3.5% of lauric acid, and 1.8% of heptadecanoic acid; as well as 1% (by weight) of

phospholipid Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...

s and about 0.3% of

glycolipid Glycolipids are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the conne ...

s. No explanation was given for these discrepancies.

References

Ya-Chi Chen, A. Zlatkis, B. S. Middleditch, J. Cowles, and W. Scheld (1987): "Lipids of contemporary stillingia oil". ''Chromatographia'', volume 23, pages 240–242. B. S. J. Jeffrey F. B. Padley (1991): "Chinese vegetable tallow - Characterization and contamination by stillingia oil". ''Journal of the American Oil Chemists' Society'', Yun Liu, Hong-lingXin, and Yun-junYan (2009): "Physicochemical properties of stillingia oil: Feasibility for biodiesel production by enzyme transesterification". ''Industrial Crops and Products'', volume 30, issue 3, pages 431-436. K. Aitzetmüller, Yaonian Xin, Gisela Werner, and Margaretha Grönheim (1992): "High-performance liquid chromatographic investigations of stillingia oil". ''Journal of Chromatography A'', volume 603, issues 1–2, pages 165-173. Hans-Joachim Esser (2002)
"A revision of ''Triadica'' Lour. (Euphorbiaceae)"
''Harvard Papers in Botany'', volume 7, issue 1, pages 17-21 (5 pages) A. Crossley and T. P. Hilditch (1950): "The component acids of some authentic and commercial stillingia oils". ''Journal of the Science of Food and Agriculture'', volume 1, issue 10, pages 292–300. J. Devine (1950): "The composition of stillingia oil and the presence therein of 2:4-decadienoic acid". ''Journal of the Science of Food and Agriculture'', volume 1, issue 3, pages 88–92. A. Crossley and T. P. Hilditch (1953): "The component glycerides of stillingia oil". ''Journal of the Science of Food and Agriculture'', volume 4, pages 38–44, {{doi, 10.1002/jsfa.2740040107

FAO The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

(1994):
Vegetable and animal oils and fats
. Chapter in ''Definition and Classification of Commodities''. Accessed on 2006-11-19. Vegetable oils