Sensory quality and metabolite dynamics in an organic selenium-enriched milk fermented by Geotrichum candidum

This study explores selenium enrichment of milk through microbial transformation, utilizing Geotrichum candidum LG-8, isolated from traditional dairy products. A combination of electronic tongue, electronic nose, HPLC-ICP-MS, and UHPLC-QTOF-MS were used to evaluate milk quality, organic selenium types, and various components. The milk retained a weakly acidic pH post-transformation, with a flavor profile rich in sour, sweet, and umami tastes. Odor analysis revealed predominant contributions from nitrogen oxides, aromatic compounds, ketones, and organic sulfides. Selenium concentrations increased with higher initial selenium levels, with 50 μg/mL yielding concentrations of MeSeCys, SeCys2, Se(IV), SeMet, and Se(VI) at 5.15, 20.80, 1.41, 75.31 and 0.44 μg/L respectively. Significant changes were observed in the milk's amino acid profile, with metabolite identification and metabolic pathways mapping(including KEGG). The findings highlight the potential of Geotrichum candidum LG-8 for generating functional organic selenium-enriched milk, offering promising nutritional benefits in dairy production.