Names | |
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Preferred IUPAC name 3-Chloropropane-1,2-diol | |
Other names 3-Monochloropropane-1,2-diol; α-Chlorohydrin; Glycerol α-monochlorohydrin; Chlorodeoxyglycerol; 3-Chloro-1,2-propanediol | |
Identifiers | |
3D model (JSmol) | |
635684 | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.002.267 |
EC Number |
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68752 | |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C3H7ClO2 | |
Molar mass | 110.54 g·mol−1 |
Appearance | Viscous, colorless liquid |
Density | 1.32 g·cm−3 |
Melting point | −40 °C (−40 °F; 233 K) |
Boiling point | 213 °C (415 °F; 486 K) |
Hazards | |
GHS labelling: | |
Danger | |
H300, H312, H315, H318, H330, H351, H360, H370, H372 | |
P201, P202, P260, P261, P264, P270, P271, P280, P281, P284, P301+P310, P302+P352, P304+P340, P305+P351+P338, P307+P311, P308+P313, P310, P311, P312, P314, P320, P321, P322, P330, P332+P313, P362, P363, P403+P233, P405, P501 | |
Safety data sheet (SDS) | External MSDS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
3-MCPD (3-monochloropropane-1,2-diol or 3-chloropropane-1,2-diol) is an organic chemical compound with the formula HOCH2CH(OH)CH2Cl. It is a colorless liquid. The compound has attracted notoreity as the most common member of chemical food contaminants known as chloropropanols. [1] It is suspected to be carcinogenic in humans. [2]
3-MCPD, together with its isomer 2-MCPD, is thought to be produced when fat-containing foods are treated at high temperatures with hydrochloric acid. Such treatments are sometimes used to accelerate protein hydrolysis, making food more digestable. In such a treatment chloride is thought to react with the glycerol backbone of lipids to produce 3-MCPD and 2-MCPD. Chlorination of glycerol gives the 3-MCPD:
The same compound can be produced by hydrolysis of epichlorohydrin. [3]
In 2009, 3-MCPD was found in some East Asian and Southeast Asian sauces such as oyster sauce, Hoisin sauce, and soy sauce. [4] Using hydrochloric acid is far faster than traditional slow fermentation. A 2013 European Food Safety Authority report indicated margarine, vegetable oils (excluding walnut oil), preserved meats, bread, and fine bakery wares as major sources in Europe. [5]
3-MCPD can also be found in many paper products treated with polyamidoamine-epichlorohydrin wet-strength resins. [6]
The International Agency for Research on Cancer has classified 3-MCPD as Group 2B, "possibly carcinogenic to humans". [7] 3-MCPD is carcinogenic in rodents via a non-genotoxic mechanism. [8] It is able to cross the blood-testis barrier and blood–brain barrier. [9] The oral LD50 of 3-chloro-1,2-propanediol is 152 mg/kg bodyweight in rats. [10]
3-MCPD also has male antifertility effects [10] [11] and can be used as a rat chemosterilant. [12]
The joint Food Standards Australia New Zealand (FSANZ) set a limit for 3-MCPD in soy sauce of 0.02 mg/kg, in line with European Commission standards which came into force in the EU in April 2002.
In 2000, a survey of soy sauces and similar products available in the UK was carried out by the Joint Ministry of Agriculture, Fisheries and Food/Department of Health Food Safety and Standards Group (JFSSG) and reported more than half of the samples collected from retail outlets contained various levels of 3-MCPD. [13]
In 2001, the United Kingdom Food Standards Agency (FSA) found in tests of various oyster sauces and soy sauces that 22% of samples contained 3-MCPD at levels considerably higher than those deemed safe by the European Union. About two-thirds of these samples also contained a second chloropropanol called 1,3-dichloropropane-2-ol (1,3-DCP) which experts advise should not be present at any levels in food. Both chemicals have the potential to cause cancer and the Agency recommended that the affected products be withdrawn from shelves and avoided. [14] [15]
In 2001, the FSA and Food Standards Australia New Zealand (FSANZ) singled out brands and products imported from Thailand, China, Hong Kong, and Taiwan. Brands named in the British warning include Golden Mountain, King Imperial, Pearl River Bridge, Golden Mark, Kimlan, Golden Swan, Sinsin, Tung Chun, and Wanjasham soy sauce. Knorr soy sauce was also implicated, as well as Uni-President Enterprises Corporation creamy soy sauce from Taiwan, Silver Swan soy sauce from the Philippines, Ta Tun soy bean sauce from Taiwan, Tau Vi Yeu seasoning sauce and Soya bean sauce from Vietnam, Zu Miao Fo Shan soy superior sauce and Mushroom soy sauce from China and Golden Mountain and Lee Kum Kee chicken marinade. [16] [17] [18] Between 2002 and 2004, relatively high levels of 3-MCPD and other chloropropanols were found in soy sauce and other foods in China. [19]
In 2007, in Vietnam, 3-MCPD was found in toxic levels. In 2004, the HCM City Institute of Hygiene and Public Health found 33 of 41 sample of soy sauce with high rates of 3-MCPD, including six samples with up to 11,000 to 18,000 times more 3-MPCD than permitted, an increase over 23 to 5,644 times in 2001, [20] The newspaper Thanh Nien Daily commented, "Health agencies have known that Vietnamese soy sauce, the country's second most popular sauce after fish sauce, has been chock full of cancer agents since at least 2001." [21]
In March 2008, in Australia, "carcinogens" were found in soy sauces, and Australians were advised to avoid soy sauce. [22]
In November 2008, Britain's Food Standards Agency reported a wide range of household name food products from sliced bread to crackers, beefburgers and cheese with 3-MCPD above safe limits. Relatively high levels of the chemical were found in popular brands such as Mother's Pride, Jacobs crackers, John West, Kraft Dairylea and McVitie's Krackawheat. The same study also found relatively high levels in a range of supermarket own-brands, including Tesco char-grilled beefburgers, Sainsbury's Hot 'n Spicy Chicken Drumsticks and digestive biscuits from Asda. The highest levels of 3-MCPD found in a non- soy sauce product, crackers, was 134μg/kg. The highest level of 3-MCPD found in soy sauce was 93,000μg/kg, 700 times higher.
In 2006 the legal limit for 3-MCPD contained in acid-hydrolysed vegetable protein (HVP) and soy sauce was set at 20μg/kg, the legislation was revised further in 2020 to limit the amount of 3-MCPD across all vegetable oils and fats as well as oils made from marine life which are either produced and made available for consumers or added as an ingredient to other foods. [23]
In 2016, the occurrence of 3-MCPD in selected paper products (coffee filters, tea bags, disposable paper hot beverage cups, milk paperboard containers, paper towels) sold on the Canadian and German market was reported and the transfer of 3-MCPD from those products to beverages was investigated. [24] Exposure to 3-MCPD from packaging material would likely constitute only a small percentage of overall dietary exposure when compared to the intake of processed oils/fats containing 3-MCPD equivalent (in form of fatty acid esters) which are often present at levels of about 0.2-2μg/g.
A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils.
Soy sauce is a liquid condiment of Chinese origin, traditionally made from a fermented paste of soybeans, roasted grain, brine, and Aspergillus oryzae or Aspergillus sojae molds. It is recognized for its saltiness and pronounced umami taste.
Glycerol, also called glycerine or glycerin, 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 as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Because of its three hydroxyl groups, glycerol is miscible with water and is hygroscopic in nature.
Propylene glycol (IUPAC name: propane-1,2-diol) is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. As it contains two alcohol groups, it is classed as a diol. It is miscible with a broad range of solvents, including water, acetone, and chloroform. In general, glycols are non-irritating and have very low volatility.
A diol is a chemical compound containing two hydroxyl groups. An aliphatic diol may also be called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. They are used as protecting groups of carbonyl groups, making them essential in synthesis of organic chemistry.
Propylene oxide is an acutely toxic and carcinogenic organic compound with the molecular formula C3H6O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its use for the production of polyether polyols for use in making polyurethane plastics. It is a chiral epoxide, although it is commonly used as a racemic mixture.
In organic chemistry a halohydrin is a functional group in which a halogen and a hydroxyl are bonded to adjacent carbon atoms, which otherwise bear only hydrogen or hydrocarbyl groups. The term only applies to saturated motifs, as such compounds like 2-chlorophenol would not normally be considered halohydrins. Megatons of some chlorohydrins, e.g. propylene chlorohydrin, are produced annually as precursors to polymers.
IARC group 2B substances, mixtures and exposure circumstances are those that have been classified as "possibly carcinogenic to humans" by the International Agency for Research on Cancer (IARC) as This category is used when there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is insufficient evidence of carcinogenicity in humans but sufficient evidence in experimental animals. In some cases, an agent, mixture, or exposure circumstance with inadequate evidence of carcinogenicity in humans but limited evidence in experimental animals, combined with supporting evidence from other relevant data, may be included in this group.
Hydrolyzed vegetable protein (HVP) products are foodstuffs obtained by protein hydrolysis and are used as ingredients to create a bouillon (broth) taste without the vegetables, bones, simmering, or other standard elements of creating bouillon from scratch.
Toxic oil syndrome (TOS) or simply toxic syndrome is a musculoskeletal disease. A 1981 outbreak in Spain which affected about 25,600 people, with over 4,000 dying within a few months and a few thousand remaining disabled, is thought to have been caused by contaminated colza (rapeseed) oil. It was unique because of its size, the novelty of the clinical condition, and the complexity of its aetiology. Its first appearance was as a lung disease, with unusual features, though the symptoms initially resembled a lung infection. The disease appeared to be restricted to certain geographical localities, and several members of a family could be affected, even while their neighbours had no symptoms. Following the acute phase, a range of other chronic symptoms was apparent.
Epichlorohydrin is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar organic solvents. It is a chiral molecule generally existing as a racemic mixture of right-handed and left-handed enantiomers. Epichlorohydrin is a highly reactive electrophilic compound and is used in the production of glycerol, plastics, epoxy glues and resins, epoxy diluents and elastomers.
Polyglycerol polyricinoleate (PGPR), E476, is an emulsifier made from glycerol and fatty acids. In chocolate, compound chocolate and similar coatings, PGPR is mainly used with another substance like lecithin to reduce viscosity. It is used at low levels, and works by decreasing the friction between the solid particles in molten chocolate, reducing the yield stress so that it flows more easily, approaching the behaviour of a Newtonian fluid. It can also be used as an emulsifier in spreads and in salad dressings, or to improve the texture of baked goods. It is made up of a short chain of glycerol molecules connected by ether bonds, with ricinoleic acid side chains connected by ester bonds.
Glycidol is an organic compound with the formula HOCH2CHOCH2. The molecule contains both epoxide and alcohol functional groups. Being simple to make and bifunctional, it has a variety of industrial uses. The compound is a colorless, slightly viscous liquid that is slightly unstable and is not often encountered in pure form.
A food contaminant is a harmful chemical or microorganism present in food, which can cause illness to the consumer.
The enzyme propanediol dehydratase (EC 4.2.1.28) catalyzes the chemical reaction
Oyster sauce describes a number of sauces made by cooking oysters. The most common in modern use is a viscous dark brown condiment made from oyster extracts, sugar, salt and water, thickened with corn starch.
Chloropropanols are chlorohydrins related to propanols containing chloride functional group. Eight isomers are possible. Two of these derivatives, 1,3-dichloropropanol (1,3-DCP) and 3-chloropropane-1,2-diol (3-MCPD), are carcinogenic contaminants in processed foods. Several isomers are encountered in industrial chemistry.
1,3-Dichloropropan-2-ol (1,3-DCP) is an organic compound with the formula HOCH2CHClCH2Cl. It is a colorless liquid. It is an intermediate in the production of epichlorohydrin.
Glycerol-1,2-carbonate is formally the cyclic ester of carbonic acid with glycerol and has aroused great interest as a possible product from the "waste materials" carbon dioxide CO2 and glycerol (especially from biodiesel production) with a wide range of applications.
2-MCPD (2-chloropropane-1,3-diol) is an organic chemical compound with the formula ClCH(CH2 )2. It is a colorless liquid. The compound has attracted notoreity as a food contaminant. Together with with the 3-MCPD, it is one of two chloropropanols food contaminants. It is suspected to be carcinogenic in humans.