Investigation on the Pyrolysis Behavior of Both Tryptophan and Tyrosine Under Conditions Mimicking Cigarette Combustion

Abstract

Both tryptophan (Trp) and tyrosine (Tyr) play a significant role in the formation of volatile compounds in processes such as food processing and cigarette combustion. While the metabolic pathways of these amino acids have been extensively studied, their pyrolysis under cigarette-like conditions remains poorly understood. This study investigates the behavior of Trp and Tyr under conditions mimicking cigarette combustion using online pyrolysis-gas chromatography/mass spectrometry. Both amino acids were subjected to pyrolysis and analyzed using online pyrolysis-gas chromatography/mass spectrometry. Key findings reveal: (1) Pyrolysis of Trp and Tyr produced over 85 and 69 volatile compounds, respectively, with more than 98% of them containing aromatic rings. (2) The predominant pyrolysates were tyramine (46.92%) for Tyr and 3-methyl indole (46.19%) for Trp. (3) Key products included 3-methyl indole and indole from Trp, and p-methyl phenol (31.45%) and phenol (7.77%) from Tyr, resulting from cleavage of C2-C3 and C3-C4 bonds. (4) Pyrolysis products profiles proposed that the primary pyrolytic pathways included decarboxylation and cleavage of the C2-C3 and C3-C4 bonds. This research provides new insights into the pyrolytic behavior of Trp and Tyr, offering a better understanding of their role in smoke aroma and contributing to the broader field of pyrolysis chemistry in food science, smoke chemistry, and biomatrices utilization.