Abstract: The background value and traceability of endogenous benzoic acid in soy sauce were investigated and analyzed. All traced samples were collected from producers of soy sauce, and benzoic acid was detected in all samples of crude soy sauce and zero-additive soy sauce at levels ranging from 7.52 to 17.09 mg/kg with an average of 12.72 mg/kg. The average contents of benzoic acid in pre-sale and final zero-additive soy sauce were 13.15 and 13.31 mg/kg, respectively. Benzoic acid content and the δ13C value of benzoic acid were followed up during soy sauce production, showing that benzoic acid in soy sauce came mainly from the raw materials. As a result of the degradation of phenylalanine, the content of benzoic acid increased during the shelf life, with an average annual increase rate of 14.26% and an annual increment of 1.80 mg/kg. Significant differences existed in the content of benzoic acid in regular and zero-additive soy sauce from different manufacturers. The average content of benzoic acid in zero-additive soy sauce was 13.38 mg/kg, which was consistent with the tracing results during the production process. The?results from this study will provide basic data for the regulation of the zero-additive soy sauce market.

Key words: benzoic acid; soy sauce; background value; precursor substances; traceability analysis