Selection of appropriate post-harvest processing methods based on the metabolomics analysis of Salvia miltiorrhiza Bunge

Post-harvest processing is a leading cause of metabolic changes and quality loss in food products. An untargeted metabolomics approach based on UHPLC-QTOF-MS was conducted to explain metabolic changes during post-harvest processing of Salvia miltiorrhiza. A rapid identification method was established for comprehensive characterization of 56 phenolic acids and 45 tanshinones. Enzymatic browning was found to be the primary factor impacting the metabolic profile. A decreasing in free phenolic acids along with increasing in bound polyphenols was observed correlated with the deepening of browning degree. The various substructures of bound polyphenols were explored to interpret the composition of browning-associated products. It has also been found that the steaming process and control of the moisture content during slicing can effectively reduce the influence of enzymatic browning. This metabolomics study will contribute to select the optimal post-harvest processing methods for S. miltiorrhiza and provide information for post-harvest processing of similar products.