Effect of microwave and infrared on the wine-drying efficiency, quality and volatile compounds of Radix paeoniae Alba

In this study, hot air drying (HD), microwave drying (MD), infrared drying (IRD) and microwave assisted infrared drying (MID) technologies were used in the wine-drying process of Radix paeoniae Alba (RPA). The effect of drying techniques on drying kinetics, temperature distribution, color profile, microstructure, crystal structure and volatile components of dried RPA were investigated. The results revealed that MID technology improved drying efficiency and uniformity, achieving the shortest drying time of 11 min. The MID method resulted in the most significant color change (ΔE = 9.8). Microwave and infrared caused the collapse of surface structure, while microwave specifically damaged the protein structure. A total of 60 volatile compounds were identified in RPA and their dried products, with organosilicon, phenols and esters being the main volatile components. The wine-drying process intensified the "wine aroma" of the dried RPA, and the destruction of structure by MID method promoted the release of organosilicon and paeonol.