Quality Characteristics Analysis of Gastrodia elata Fermentation Broth by Microbial Co-fermentation

To investigate the impact of compound microbial fermentation on Gastrodia elata quality (fermented liquid), providing a theoretical foundation for its industrial deep processing. Gastrodia elata was fermented using a compound microbial consortium (Lactobacillus plantarum, Acetobacter pasteurianus, and Wickerhamomyces anomalus; FJ group), with unfermented (CK) and enzymatically hydrolyzed (MJ) groups as controls. Physicochemical properties (total acidity, pH, etc.) were assessed. HPLC analyzed gastrodin, p-hydroxybenzyl alcohol, determined total phenols, and total flavonoids, evaluated their antioxidant and hypoglycemic activities. Volatile compounds and differential metabolites were identified using SPME-GC-MS. Sensory evaluation assessed overall quality and flavor. The results showed that compared to CK, FJ significantly increased total acidity (2.6-fold), decreased pH, and elevated crude polysaccharides (247.65±16.10 mg/g) and ethanol (0.54%vol±0.02%vol). MJ showed minimal physicochemical changes except in polysaccharides. HPLC revealed that microbial fermentation enhanced the production of bioactive compounds (gastrodin, p-hydroxybenzyl alcohol), significantly increasing total phenols (promote 29.45% vs. CK), total flavonoids (promote 44.08% vs. CK), antioxidant activity, and hypoglycemic activity (FJ>MJ>CK). SPME-GC-MS identified increased alcohols, acids, and esters in FJ, with characteristic differential metabolites including 3-penten-2-one, isoamyl alcohol, phenethyl alcohol, and ethyl acetate. Sensory evaluation confirmed improved quality, imparting distinct alcoholic and sweet notes. These results provide that compound microbial fermentation effectively enhances the bioactive components, functional properties, and sensory quality of Gastrodia elata, offering valuable insights for developing functional foods and advancing its industrial processing.