Hot air-microwave combination drying method for processing Angelicae Sinensis Radix / 中草药

ABSTRACT

Objective: In this study, the feasibility of hot air-microwave combination drying method for processing Angelicae Sinensis Radix (ASR) was investigated and evaluated. Methods: Hot air temperature, drying time, microwave electric current, and microwave time were taken into consideration. The combined drying method was optimized based on the standards of ASR documented in Chinese Pharmacopoeia (2015 version). After that, microorganisms, heavy metals, harmful elements, and active ingredients (ferulic acid, coniferyl ferulate, senkyunolide I, senkyunolide H, senkyunolide A, E-ligustilide, Z-ligustilide, n-butylidenephthalide, riligustilide, and levistilide A) were detected to evaluate the quality of processed samples. Results: The optimal method was that samples were dried in hot air (70℃) for 20 h, then heated in microwave (100 mA) for 6 min. The number of microorganisms in processed samples equaled to sulfur-fumigated samples; Heavy metals and harmful elements were qualified after this processing; The new drying method for processing ASR had no significant effect on the active ingredient. Conclusion: After this process, the physical and chemical indicators of ASR are in line with the criteria of Chinese Pharmacopoeia. This hot air-microwave combination drying method should be a fast drying method for post-harvest handling of ASR.