2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation and fate: an example of the coordinate contribution of lipid oxidation and Maillard reaction to the production and elimination of processing-related food toxicants

Abstract

2-Amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) is produced by reaction of phenylacetaldehyde, the Strecker aldehyde of phenylalanine, with creati(ni)ne in the presence of formaldehyde and ammonia, which are formed in situ. Traditionally, the carbonyls compounds required 10 for the formation of PhIP ring were considered to be produced as a consequence of Maillard reaction between phenylalanine and carbohydrates. This review collects all recent evidences suggesting that lipids can also contribute to produce the Strecker degradation of phenylalanine and the formation of formaldehyde analogously to carbohydrates. Furthermore, lipid-derived reactive carbonyls not only contribute to PhIP formation but they can also be involved in PhIP fate observed in the presence of 15 oxidized oils. This role has not been yet investigated for carbohydrate-derived reactive carbonyls but it might be hypothesised to take place because of the decrease of PhIP observed when excess of monosacharides is employed to study PhIP formation. All these results suggest that carbohydrates and lipids can contribute simultaneously to PhIP formation and fate. This is another example of the simultaneous contribution of both lipids and carbohydrates to the carbonyl chemistry that takes place in 20 foods upon processing and/or storage. Furthermore, many of these conclusions can also be extended to the formation of other aminoimidazoazarenes with structure of imidazopyridine.

The effects of different frying oils on the formation of heterocyclic aromatic amines in meatballs and the changes in fatty acid compositions of meatballs and frying oils

“…Guillen and Uriarte reported that linoleic acid is associated with the formation of potentially toxic compounds such as free radicals, aldehydes, and ketones. These reactive oxygen species (ROS), formed by the peroxidation of USFA, can cause decomposition of Amadori compounds and development of intermediates for the formation of Strecker aldehydes, pyrazines, and pyridines in the Maillard reaction, and can eventually contribute to the formation of HCAs . However, it is also known that vegetable oils contain antioxidants such as vitamin E, β ‐carotene and phenolic compounds at different levels .…”

“…Phenolic compounds could also inhibit the formation of imidazoquinoxaline‐type HCAs by holding pyrazine cation radicals and some other carbon‐centered radicals, which formed during the Maillard reaction, or by different routes. Phenolic compounds can also bind carbonyl compounds efficiently in the conversion of phenylalanine in Strecker degradation to phenylacetaldehyde, which is an intermediate in the formation of PhIP . On the other hand, it is determined that the formation of PhIP is directly related to the temperature, and at 175–200 °C temperatures, the formation of PhIP is at low levels while at temperatures above 200 °C there are significant increases in PhIP content …”

“…These reactive oxygen species (ROS), formed by the peroxidation of USFA, can cause decomposition of Amadori compounds and development of intermediates for the formation of Strecker aldehydes, pyrazines, and pyridines in the Maillard reaction, and can eventually contribute to the formation of HCAs. 32 However, it is also known that vegetable oils contain antioxidants such as vitamin E, -carotene and phenolic compounds at different levels. 23 In the present study, it is known that all frying oils used contain natural antioxidants, 9,11 although antioxidant analysis in oils was not done.…”

“…Phenolic compounds can also bind carbonyl compounds efficiently in the conversion of phenylalanine in Strecker degradation to phenylacetaldehyde, which is an intermediate in the formation of PhIP. 32 On the other hand, it is determined that the formation of PhIP is directly related to the temperature, and at 175-200 ∘ C temperatures, the formation of PhIP is at low levels while at temperatures above 200 ∘ C there are significant increases in PhIP content. 22 Britt et al 25 determined that the total HCA (IQ, MeIQ, MeIQx, 4,8-DiMeIQx and PhIP) content was 25.6 ng g −1 in meatballs with wileyonlinelibrary.com/jsfa 15% fat fried at 170 ∘ C for 16 min.…”

The effective inhibition of the formation of heterocyclic aromatic amines via adding black pepper in fried tilapia fillets

“…This increased concentration was a result of the Maillard reaction during frying process. Pyridine, a Strecker degradation product in Maillard reaction, can form PhIP by reacting with aldehydes and creatinine through free radical mechanism or others (Zamora & Hidalgo, 2015). On the contrary, the addition of black pepper considerably inhibited the formation of PhIP and the maximum inhibition reached 100%.…”