Physicochemical properties, non-volatile flavor components and antioxidant activity analysis of Ganoderma lucidum (Curtis) P. Karst. extracts dried by different methods

The objective of this present study is to evaluate the effect of different drying methods (spray drying, freeze drying and hot-air drying) on physicochemical properties and antioxidant ability of G. lucidum extracts (GLEs) using various techniques. Meanwhile, combined with free amino acids (FAA) analysis, taste activity values (TAV) analysis and electronic tongue to investigate the relationship between the drying method and the sensory quality of GLEs. The study demonstrates that spray drying GLEs (SDE) has a high water solubility of 96.04% ± 0.10% due to its low crystallinity and hollow spherical microstructure. SDE and freeze drying GLEs (FDE) contain high levels of polysaccharides and proteins, which facilitates the formation of polysaccharide-protein chelates, thereby improving antioxidant capacity. However, SDE has higher antioxidant activity when its polysaccharide content is the same. SDE has higher thermal stability to maintain the molecular structure of GLEs. Meanwhile, FDE has a bitter FAAs content up to 65.84 ± 1.12 mg/g and TAV of Histidine is 178.70. Overall, the results suggest that spray drying is an appropriate and preferred drying method to maintain the bioactivity and bioavailability of GLEs. These findings may enhance the understanding of the GLEs flavor property and bioavailability associated with drying methods and provide a theoretical basis for G. lucidum processing.