Study on vacuum drying process of extract paste of Huangqi Baihe Granules based on Box-Behnken design-response surface and G1-entropy method / 中草药

ABSTRACT

Objective To optimize the vacuum drying process of extract paste of Huangqi Baihe Granules (HBG) and evaluate the physical quality of powder. Methods With drying temperature, vacuum degree, and material thickness as independent variables, the comprehensive evaluating indexes of content of calycosin 7-O-β-D-glucopyranoside, hesperidin, crude polysaccharide, ethanol extraction amount, and drying rate as response values, Box-Behnken design-response surface methodology and G1-entropy method were used to optimize the vacuum drying process. The similarity of fingerprints between extract powder dried by the optimized technology and extract paste was compared. Additionally, the properties of powder were evaluated comprehensively with nine physical indicators, including relative homogeneity index, bulk density, tap density, interparticle porosity, compressibility, Hausner ratio, angle of repose, moisture content, and hygroscopicity. The physical fingerprint of powder were established to evaluate the quality consistency of different batches of extract powder. Results The optimal drying parameter was as follows the drying temperature was 68 ℃, the vacuum degree was 0.07 MPa, the material thickness was 6 mm. Three verification experiments were carried out under these conditions and the average comprehensive evaluating indexes of vacuum drying was 91.05, which was close to the model prediction 91.87, and the relative error was 0.89%. Compared with the extract paste, the similarity of fingerprint of extract powder were more than 0.91. The similarity of chemical and physical fingerprint of three batches of extract powder were higher than 0.99. Conclusion The optimized vacuum drying technology of extract paste of HBG is stable and feasible.