Effects of fermentation on biochemical parameters, antioxidant capacity and flavour quality of a plant-based beverage prepared from highland barley and Potentilla anserina L

Highland barley and Potentilla anserina L. (juema) were used for the first time as substrates for fermentation with Lactiplantibacillus plantarum LL6-1 over a period of 0-9 days. Changes in physicochemical parameters, antioxidant activities and flavour profiles were systematically evaluated. Lactic acid became the predominant organic acid after fermentation, whereas total phenols, free amino acids and reducing sugars peaked on day 1. Flavonoid content and hydroxyl radical scavenging activity increased throughout the process, while SOD activity and DPPH radical scavenging capacity rose initially and then declined. Correlation analysis revealed that 16 of the 17 detected compounds were positively intercorrelated, with acetic acid as the sole exception. Fermentation markedly improved sensory characteristics: bitterness, bitter aftertaste and astringent aftertaste were significantly reduced. Electronic nose analysis clearly discriminated samples from different fermentation stages. A total of 17 new volatile compounds were identified after fermentation, and the total flavour compound content increased 3.2-to 8.2-fold compared with that before fermentation, peaking on day 2. Esters and alcohols became the dominant volatile constituents. Collectively, these findings demonstrate that LL6-1 fermentation effectively eliminates off-odours and substantially enhances the aroma quality of the beverage, indicating that this strain holds considerable promise for the development of novel plant‑based fermented beverages.