Alterations in Functional Constituents and Bioactivities of Tartary Buckwheat via Solid-State Fermentation with Three Edible-Medicinal Fungi: A Metabolomics-Based Analysis

To functionally enhance Tartary buckwheat and elucidate the underlying mechanisms of change, solid-state fermentation (SSF) was conducted using three edible-medicinal fungi-<i>Auricularia auricula</i> (<i>A. auricula</i>), <i>Ganoderma lucidum</i> (<i>G. lucidum</i>), and <i>Hericium erinaceus</i> (<i>H. erinaceus</i>). The in vitro antioxidant (DPPH/ABTS) and α-glucosidase inhibitory activities were quantitatively evaluated. Notably, SSF with <i>H. erinaceus</i> specifically elevated α-glucosidase inhibitory activity by 50% under the tested conditions. Non-targeted metabolomics further profiled metabolite alterations to identify key up-regulated bioactive compounds. Epicatechin gallate (ECG) was significantly up-regulated in all three samples, and the fold change in quercetin 3'-O-sulfate in GFTB was significantly higher than that in the other two samples. Metabolic pathway analysis identified the biosynthesis of secondary metabolites and the metabolism of terpenoids and polyketides as the most prominently affected pathways. This study demonstrates that SSF with edible-medicinal fungi is an effective bioprocessing strategy to boost the bioactivity and value of Tartary buckwheat.