Ultrafiltration matrix modulates metabolism and flavor profiles in natural cheese: Insights from microbial and metabolomic profiling.

Ultrafiltration (UF) technology has considerable potential for improving cheese yield and reducing whey discharge; however, its effects on microbial metabolism and flavor formation remain unclear. In this study, untargeted metabolomics, flavoromics, and 16S rRNA gene sequencing were integrated to evaluate metabolic and microbial variations in UF cheese. UF treatment was associated with marked changes in primary and secondary metabolite profiles, including increased levels of umami- and sweet-related amino acids. Differential metabolites were mainly enriched in pathways related to D-amino acid metabolism, starch and sucrose metabolism, and galactose metabolism. UF cheese also exhibited higher levels of key aroma compounds, particularly 2-pentanone, δ-octalactone, and benzyl alcohol, which were associated with fruity and creamy odor descriptors. Correlation analysis suggested that Lactococcus was associated with methyl ketones and lactones, whereas Streptococcus was associated with specific alcohol compounds. These findings provide insights into flavor formation and microbial-metabolite relationships in UF cheese.