Integration of volatile and non-volatile metabolite profile, and in vitro digestion reveals the differences between different preparation methods on physico-chemical and biological properties of Gastrodia elata

Gastrodia elata Blume ( G. elata ) is a traditional medicinal and edible plant whose quality is significantly influenced by post-harvest processing. To obtain an optimal post-harvest processing method for G. elata , this study employed sensory evaluation, scanning electron microscopy (SEM), gas chromatography-ion mobility spectrometry (GC-IMS), and non-targeted metabolomics, in conjunction with an in vitro digestion model, to assess the impact of different processing and drying methods on the quality of G. elata . The findings showed that the steam treatment followed by heat pump drying resulted in the highest levels of total phenols, total flavonoids, and polysaccharides in G. elata , and caused more pronounced damage to its microstructure. This treatment also maintained the highest antioxidant activities and optimal acetylcholinesterase (AChE) inhibition capacity throughout in vitro digestion, meanwhile, effectively eliminating the unpleasant odor and achieving the highest sensory scores. Furthermore, non-targeted metabolomic analysis revealed noteworthy alterations in the metabolite profile of G. elata , mainly related to purine metabolism and the biosynthesis of amino acids pathways. This study provides valuable insights into the post-harvest processing of G. elata .