ABSTRACT
Objective: To evaluate the feasibility of heat-treating de-sulfur method for sulfur-fumigated Codonopsis Radix (CR) by investigating the changes in contents of sulfur dioxide residue and sulfur-containing derivatives after sulfur-fumigation.Method: Qualitative and semi-quantitative characterization of sulfur-containing derivatives was analyzed by ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS/MS),and sulfur dioxide residues were determined by acid-base titration method. Then the correlations between sulfur dioxide residues and sulfur-containing derivatives in sulfur-fumigated CR samples with different sulfur-fumigation and heat treatment extents were analyzed.Result: Atractylenolide Ⅱ and atractylenolide Ⅲ sulfur-containing derivatives were identified as major characteristic markers of sulfur fumigated CR. With the increase of sulfur-fumigation time,the content of sulfur dioxide residues was continuously increased,while the content of sulfur-containing derivatives was elevated at the beginning and then reached to a plateau, so there was not necessarily a positive correlation between sulfur dioxide residue and the amount of sulfur derivatives. With the increase of heat-treated time,the content of sulfur dioxide residues was continuously decreased,while the content of sulfur-containing derivatives was decreased first and remained at a high level later. There was no clear correlation between sulfur dioxide residue and sulfur-containing derivatives in different sulfur-fumigated and heat-treating de-sulfur degrees of CR.Conclusion: Heat-treatment could decrease the content of sulfur dioxide residue,but the content of sulfur-containing derivatives still remained at a high level, so heat treatment could not reinstate the inner quality of sulfur-fumigated CR to its non-fumigated ones. Therefore, heat-treating de-sulfur is not a feasible method for the quality assurance of sulfur-fumigated CR.