Effect of fermentation on the quality of Liberica coffee (Coffea liberica) using Lactiplantibacillus plantarum and Leuconostoc mesenteroides bacteria: Sensory analysis, volatile compound, antioxidant, and proximate analysis

Fermentation is a critical post-harvest process in coffee production because microbial metabolism can alter chemical composition and sensory quality. This study evaluated the effects of fermentation with Lactiplantibacillus plantarum , Leuconostoc mesenteroides , and their combination on the sensory properties, bioactive compounds, antioxidant activity, and proximate composition of Liberica coffee. Coffee samples were subjected to single- and mixed-culture fermentation for 48 and 72 h. Fermentation altered the total phenolic and flavonoid contents and improved antioxidant activity in all fermented treatments, as indicated by lower IC 50 values than the unfermented control, although the magnitude of the changes varied among treatments. Caffeine concentration decreased progressively following fermentation, whereas chlorogenic acid concentration showed only minor variation among treatments. Sensory evaluation showed higher final cupping scores for all fermented samples than for the unfermented coffee, with the highest scores observed for the mixed-culture treatments after 48 and 72 h of fermentation (85.35 and 87.57, respectively). GC–MS analysis tentatively identified a profile dominated by fatty-acid-derived esters and other lipid-related compounds. However, because the solvent-based extraction was not specifically optimized for aroma-active compounds, the detected profile should not be considered a complete representation of the volatile fraction of brewed coffee. Overall, mixed-culture fermentation was associated with improved sensory scores and substantial changes in selected chemical characteristics of Liberica coffee.