Flammulina velutipes (Golden Needle Mushroom, F. velutipes) undergoes rapid postharvest deterioration characterized by browning and decay. Drying effectively extends its shelf life and processing window. This study systematically compared the quality attributes and metabolic profiles of F. velutipes subjected to different treatments: fresh F. velutipes as the control group (CK), hot-air drying (HAD), vacuum freeze drying (VFD), and natural air drying (NAD), to elucidate the underlying mechanisms of drying-induced changes. In appearance, VFD samples were uniformly bright with shape well maintained, while HAD and NAD were brownish yellow with significantly reduced volume. In terms of antioxidant capacity, VFD demonstrated the highest level, followed by HAD. A total of 2645 metabolites were identified in dried F. velutipes via metabolomics (positive/negative ion modes), primarily comprising lipids, terpenoids, polyphenols, amino acids, carbohydrates, and steroids. In contrast to VFD, both HAD and NAD showed reduced levels of certain metabolites. VFD treatment yielded the richest profile of differential metabolites in F. velutipes. These results position VFD as the superior method for preserving the quality and metabolic integrity in F. velutipes. This comparative study serves as a practical reference for selecting the most suitable drying method in the F. velutipes industry and enhances our understanding of the metabolic responses to dehydration stress.
Yang et al. (Thu,) studied this question.