Formation of Heterocyclic Amines in a Model System during Heating

Abstract

The formation of heterocyclic amines (HAs) in a model system during heating at 100, 150, or 200°C for varied lengths of time was studied. The following systems were used: (i) phenylalanine, (ii) creatinine, (iii) phenylalanine and glucose, (iv) phenylalanine and creatinine, (v) glucose and creatinine, and (vi) phenylalanine, glucose, and creatinine. Results showed that HAs could only be found in both systems of glucose and creatinine, and of phenylalanine, glucose, and creatinine. Both 2-amino-9H-pyrido-[2,3-b]indole (AαC) and 2-amino-3-methyl-9H-pyrido-[2,3-b]indole (MeAαC) were observed in the former system, and the formation rate of AαC was higher than MeAαC. For the latter system, 2-amino-3-dimethylimidazo[4,5-f]quinoxaline (IQx), 9H-pyrido-[4,3-b]indole (Norharman), 1-methyl-9H-pyrido-[4,3-b]indole (Harman), AαC, and MeAαC were present. The formation rate of AαC was the highest at 200°C, followed by MeAαC, Harman, Norharman, and IQx. In addition, the varieties of HAs increased both with increasing heating time and temperature. The amounts of HAs formed were less in the model system of glucose and creatinine than that of phenylalanine, glucose, and creatinine. The same trend was also observed for the formation rate of HAs. At 150 or 200°C, the amounts of IQx, Harman, Norharman, AαC, and MeAαC increased in the initial period of heating and then reached a plateau. The results of this study provided a basic understanding of the conditions that result in the formation of HAs during cooking of meat and fish products.