Formation of Tetrahydro-β-Carbolines in Thermally Processed Foods and Their Detection Methods

Tetrahydro-β-carbolines (THβCs) are a class of alkaloids widely existing in foods, and the formation pathways of THβCs in the human body include endogenous and exogenous ones. The endogenous pathway is related to the metabolism of tryptophan in the human body, while the exogenous pathway is mainly derived from dietary intake. The Maillard reaction and microbial metabolism in food processing are the major pathways for the formation of THβCs, and high temperature, acidic pH and long-term processing will significantly promote the formation of THβCs in foods. The biological activity of THβCs is two-fold: on one hand, its derivatives can enhance neural signaling by inhibiting monoamine oxidase (MAO) and exhibit antioxidant, antibacterial, and anti-inflammatory effects; on the other hand, its oxidation products heterocyclic amines and N-nitroso compounds have carcinogenic and mutagenic risks. At present, the commonly used detection methods for THβC in foods include gas chromatography-mass chromatography (GC-MS), high performance liquid chromatography with fluorescence detection (HPLC-FLD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and solid phase extraction (SPE) combined with HPLC-MS/MS is the mainstream method, with a detection limit of 10 ng/mL.