Differential analysis of volatile and non-volatile constituents of Epimedium koreanum Nakai processed with various mutton oils by chemometric methods.

This study aimed to systematically examine the effects of different mutton fat sources, classified by donor sex and anatomical origin, on the volatile and non-volatile metabolic profiles of Epimedium koreanum Nakai during traditional mutton fat stir-frying. The regulatory mechanisms underlying compositional variation were also investigated. A comprehensive analytical strategy integrating electronic nose analysis, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), ultra-high performance liquid chromatography-Orbitrap high-resolution mass spectrometry (UHPLCOrbitrap HRMS), and multivariate chemometric methods was used to characterize overall chemical changes. Processing markedly depleted native volatile components, including higher alcohols and unsaturated enals, in raw Epimedium koreanum Nakai, while promoting the accumulation of endogenous sheep fat components and thermal reaction products. Total flavonoids and phenolic acids in the six processed products followed the order ram abdominal fat-derived > ewe abdominal fat-derived > ram lumbar fat-derived > ewe lumbar fat-derived > ram tail fat-derived > ewe tail fat-derived. Products processed with ram fat contained 1.2-1.5-fold higher levels of characteristic flavonoid aglycones than those processed with ewe fat. Fifty-eight differential biomarkers were preliminarily screened at the threshold of VIP > 1, among which core markers with VIP > 2 were selected for subsequent pathway enrichment and correlation analysis to reduce false positive risk to select markers with robust discriminative ability and ensure the reliability of mechanistic interpretation. KEGG enrichment analysis indicated three core regulatory pathways: flavonoid biosynthesis, amino acid metabolism, and ABC transporters. These findings provide a chemical basis for optimizing Epimedium koreanum Nakai processing and establishing a standardized quality evaluation system for mutton fat-processed Epimedium koreanum Nakai products.