Carcinogenic 4(5)-Methylimidazole Found in Beverages, Sauces, and Caramel Colors: Chemical Properties, Analysis, and Biological Activities

Abstract

Since the National Toxicology Program (NTP) identified 4(5)-methylimidazole [4(5)-MI] as a cancer causing chemical in 2007 and the State of California added it to the Proposition 65 list of compounds as a carcinogen on January 7, 2011, many researchers and regulatory agencies have become focused on the presence of 4(5)-MI in foods and beverages. 4(5)-MI has been known to form in the Maillard reaction system consisting of a sugar and ammonia-a typical caramel-color preparation method for beverages. 4(5)-MI is identified in various beverages and sauces, which are colored with caramel, as well as in caramel color itself. Analysis of 4(5)-MI is extremely difficult due to its high water solubility, but the analytical method for 4(5)-MI has progressed from conventional paper chromatography, gas chromatography, and gas chromatography-mass spectrometry to the most advanced high-performance liquid chromatography-mass spectrometry. Various studies indicate that caramel colors and carbonated beverages contain 4(5)-MI in levels ranging from 0 to around 1000 ppm and from 0 to about 500 ppm, respectively. Reports of the toxicity of 4(5)-MI at relatively high levels suggest that it may cause some adverse effects on human consumers.

2-Acetyl-4-tetrahydroxybutylimidazole and 4-methylimidazole in caramel colours, vinegar and beverages in China

“…Class II compounds are manufactured by heating carbohydrates with sulfite-containing compounds. Class III compounds are created by heating carbohydrates with ammonium compounds and class IV compounds are produced by heating carbohydrates with both sulfite-containing and ammonium-containing compounds (Hengel et al, 2013). 4-Methylimidazole (4-MeI) is a simple nitrogen-containing heterocyclic compound that is known to be present in caramel coloring, which is the result of a browning reaction when nitrogen compounds are present.…”

Sustainability in Foods and Food Production: The Roles of Peer Reviewed Science and Corporate Initiatives

“…Food processors need also be aware that some processing steps can lead to formation of Maillard reaction products in foods, many of which are beneficial in terms of taste and odor but a few of which are toxic. High temperature cooking of potatoes and cooking or roasting of other high carbohydrate foods can lead to formation of acrylamide (18,19), diacetyl (20), and 4-methyl imidazole (21). Recent research shows ways to reduce acrylamide formation by a variety of approaches (22,23).…”

Determination of 4-Methylimidazole in Ammonia Caramel Using Gas Chromatography–Tandem Mass Spectrometry (GC-MS/MS)

“…One of many heterocyclic processing compounds formed in the production of ammonia caramel is 4(5)-methylimidazole (4-MeI), which is a product of Maillard reaction. At neutral to basic pH solutions there are two tautomers: 4-methylimidazole and 5-methylimidazole exist in equilibrium [2]. Methylglyoxal was proposed as the starting precursor in 4-MeI formation ( Figure 1).…”

“…In 2007 the National Toxicology Program (NTP) stated 4-methylimidazole as a cancer causing chemical and in 2011 the State of California also specified 4-methylimidazole in Proposition 65 as a carcinogen. The level of 4-MeI, which is deemed to pose no significant risk, is 29 g/day [2].…”