Abstract: 【Objective】The potential sources of co-mutagens β-carbolines 1-methyl-9H-pyrido[3,4-b]indole (harman) and 9H-pyrido[3,4-b]indole (norharman) in braised sauce meat were investigated. 【Method】 The occurrence of the bioactive β-carbolines in six braised sauce meats and five soy sauces were studied by solid-phase extraction and HPLC-DAD. Furthermore, the potential sources of β-carbolines in braised sauce mutton boiled with one of the soy sauces were determined.【Result】β-carbolines were detected in all of the six braised sauce meats and five kinds of soy sauces. The concentrations of harman in braised sauce meat were 3.71-42.32 ng•g-1, and norharman were 2.95-63.97 ng•g-1. The levels of harman and norharman in soy sauces were 111.47-301.30 ng•g-1 and 74.71-199.27 ng•g-1, respectively. Raw mutton contained undetectable amounts of harman and norharman. However, blank mutton samples, which were boiled only with water, contained harman and norharman for 3.39 and 4.05 ng•g-1. In addition, there were 17.30 ng•g-1 harman and 12.18 ng•g-1 norharman in the control samples containing soy sauce, salt and other seasonings. The proportion of harman and norharman in boiled mutton was 15% and 23%. The percentage of harman and norharman by boiling soy sauce and seasonings was 58% and 46%, respectively. Mutton reacted with soy sauce generated 27% harman and 31% norharman.【Conclusion】Both harman and norharman appeared in braised sauce meat and soy sauce, and soy sauce contained higher content of β-carbolines. Almost 50% of β-carbolines in braised sauce mutton was due to the addition of soy sauce. The pyrolysis of amino acids in mutton and the chemical reaction of soy sauce and mutton were important sources of harman and norharman.

Key words: harman , norharman , braised sauce meat , soy sauce , mutton