Abstract: To identify the flavor peptides from white sufu, analyze their amino acid sequences, and evaluate the taste characteristics of their synthetic counterparts. Methods: Ultra-filtration and glucose gel Sephedex G-15 filtration chromatography were applied to separate flavor fractions from white sufu extracts. The fraction with the best sensory evaluation was further purified by reversed phase high performance liquid chromatography (RP-HPLC). The subfraction with the maximum chromatographic peak area was identified by using matrix-assisted laser analytical ionization timeof-flight/time-of-flight mass spectrometry/mass spectrometry (MALDI-TOF/TOF MS/MS) with De Novo software. The potential flavor peptides were also artificially synthesized and their sensory properties were evaluated. Results: Three flavor peptides were obtained from white sufu. Their amino acid sequences were identified as Asp-Phe-Lys-Arg-Glu-Pro, Asp-Arg-Glu-Lys-Phe-Asp-Glu, and Asp-Glu-Asp-Phe-Lys-Arg-Glu-Pro. The first peptide had obvious umami taste. The third one had both umami and sour tastes. The second had less obvious taste although it could enhance the umami flavor of sodium glutamate solution. Conclusion: The umami flavor of white sufu not only cames from amino acids such as glutamate, but also was related to small peptides.

Key words: flavor peptide, white sufu, umami, isolation, identification