Effects of Postharvest Processing Methods on Bioactive Compounds and Taste Profile of Salvia miltiorrhiza Bunge

Salvia miltiorrhiza Bunge is an important medicinal plant whose quality is strongly influenced by postharvest processing, yet the influence of steaming and drying on bioactive compounds and sensory properties remains poorly understood. This study combined phytochemical profiling with electronic tongue analysis to examine how steaming combined with freeze-drying (FD) or oven-drying at 35, 60 and 105 °C influence bioactive compounds and taste characteristics. Drying at 105 °C significantly reduced tanshinone I, tanshinone IIA and total tanshinone concentrations, whereas FD, 35 °C and 60 °C treatments resulted in total tanshinones being kept above the Chinese Pharmacopoeia’s minimum requirement. In contrast, steaming reduced the sensitivity of salvianolic acid B concentration to subsequent drying conditions, maintaining relatively high concentrations across drying methods. All steamed and non-steamed FD samples met the pharmacopoeia requirement for salvianolic acid B content. Electronic tongue analysis of 35 °C and FD-treated samples only revealed that the effects of drying on taste profile depended on steaming treatment. The non-steamed sample dried at 35 °C exhibited reduced astringent aftertaste, umami, richness, and saltiness relative to the FD samples. Salvianolic acid B was positively correlated with richness, saltiness and astringent aftertaste and negatively associated with bitterness. Overall, steaming moderated the effects of subsequent drying on both salvianolic acid B and taste profile, suggesting that steaming may improve the consistency of postharvest quality across different drying conditions.