Comparative compositional analysis of commercially produced mule duck and Landes goose foie gras

This study compared the compositional characteristics of commercially produced foie gras from mule ducks and Landes geese by integrating solid-phase microextraction gas chromatography-mass spectrometry, untargeted metabolomics, and untargeted lipidomics. Landes goose foie gras showed a significantly greater liver weight and higher moisture content than mule duck foie gras, indicating clear product-level differences in gross traits. Volatile profiling identified 153 compounds, of which 48 differed significantly between the two groups. Mule duck foie gras displayed a volatile profile enriched in floral-, fruity-, and spice-associated compounds, whereas Landes goose foie gras was characterized by a higher abundance of compounds associated with grassy, earthy, and lipid oxidation-related notes. Untargeted metabolomics identified 834 polar metabolites, including 132 differential metabolites, suggesting additional but relatively moderate compositional divergence at the small-molecule level. Untargeted lipidomics detected 536 lipids, among which 85 differed significantly. Mule duck foie gras was characterized by a higher relative abundance of several unsaturated triglycerides and selected phospholipid species, whereas Landes goose foie gras showed enrichment of several long-chain saturated triglycerides and bile-related components. Collectively, these results demonstrate that mule duck and Landes goose foie gras can be clearly differentiated at the levels of product traits, volatile composition, polar metabolites, and lipid profiles. The observed differences are best interpreted as integrated compositional differences between two commercially produced foie gras types obtained under species-specific production regimens, and they provide a useful basis for quality evaluation, product discrimination, and further targeted studies of flavor and lipid deposition patterns.