Detection of Fermented Soy Sauce Adulteration Using Elemental Analyzer-Carbon Isotope Ratio Mass Spectrometry

In order to strengthen the supervision of the quality of fermented soy sauce (FSS), a method for FSS adulteration identification was established using elemental analyzer isotope ratio mass spectrometry (EA-IRMS). Base on the δ¹³C values of 86 authentic FSS samples from different production areas, the δ¹³C value limit for authentic FSS was proposed: the δ¹³C value of the amino acid in FSS should be lower than or equal to -21.5‰. Based on the above criteria, 15 soy sauce samples are confirmed adulterated with acid hydrolyzed protein seasoning（AHPS） in 58 commercial soy sauce samples. As a conclusion, the EA-IRMS method, as a tool of quality assuance and adulteration identification, can effectively assess the quality of fermented soy sauce.