ABSTRACT
Objective: To optimize the suitable technology of Ophiopogon japonicus (OJ) fumigation based on the changes of relative indexes after the different levels of sulfur fuming. Methods: The phenol-sulfuric acid method was used to determine the content of polysaccharide. HPLC-ELSD method was used to determine the contents of Ophiopogon saponins D (OPD) and D' (OPD') with the mobile phase of acetonitrile-water (50:50), drift tube temperature at 40℃, and nitrogen volumetric flow of 2.0 L/min. The fingerprints of OJ were determined by HPLC-UV method, the mobile phase was eluted with acetonitrile-0.1% phosphoric acid gradient, and the detection wavelength was 297 nm. The contents of ethylophiopogonanones A (MA) and B (MB) were determined using the same method. Using the contents of total polysaccharides of OJ, OPD and OPD', MA and MB, and the contents of other components in the fingerprints as control indexes, and the dosage of sulfur and the time of sulfur fumigation as factors, the central composite design-response surface methodology (CCD-RSM) was used to optimize sulfur fumigation process. Results: In the experimental design range, the content of polysaccharides increased first and then decreased with the increase of sulfur dosage and sulfur fumigation time, and the contents of OPD and OPD' increased slightly and then decreased. The contents of MA and MB were slightly reduced. The sulfur fuming process was determined as follows: sulfur dosage was 120-200 g/m3, sulfur fuming time was 0.6-1.5 h, binomial equation: Y = 0.574 + 0.054 3 X1-0.008 13 X2-0.518 X12 + 0.131X22 + 0.153 X1X2 (R-Sq = 0.971). Process validation: the absolute value of deviation was less than 3%. Conclusion: In this study, the changes of chemical composition of OJ were studied, and the sulfur smelting process suitable for OJ was established.