Enhancement of isoflavone aglycones, GABA, and mineral bioavailability in Apios americana Medikus by co-fermentation with Lactiplantibacillus plantarum LAB02 and Levilactobacillus brevis BMK484

This study evaluated metabolic and functional changes in Apios americana Medikus (AAM) during lactic acid bacteria fermentation using Lactiplantibacillus plantarum LAB02 and Levilactobacillus brevis BMK484 at different strain ratios and fermentation times. A 1:1 mixed culture fermented for 36 h was optimal. Isoflavone glycosides decreased (1.837 → 0.006 mg/g), while aglycones increased (0.097 → 0.604 mg/g), including genistein (0.194 mg/g) and 2′-hydroxygenistein (0.184 mg/g). Fermentation increased γ-aminobutyric acid (52.6 mg/100 g), aspartic acid, and extractable minerals (P, K, Ca, Mg) under the applied extraction conditions, with key unsaturated fatty acids retained. Antioxidant activity improved, with DPPH and ABTS IC₅₀ values reduced by 26.7% and 21.5%, respectively. PCA and heatmap clustering confirmed distinct shifts among dried, sterilized, and fermented AAM, supporting its use as a functional food ingredient. • Aglycone contents of AAM were maximized by fermentation at 30 °C for 36 h using a 1:1 mixed culture of L. plantarum LAB02 and L. brevis BMK484. • FeAAM simultaneously enhanced GABA (52.6 mg/100 g) and isoflavone aglycone (0.996 mg/g) contents. • Isoflavones were stepwise converted from diglycosides to aglycones from DrAAM–StAAM–FeAAM. • TPC, antioxidant activities, and digestive enzyme inhibitory activities increased progressively from DrAAM to StAAM to FeAAM.