Breed-Associated Roasted Aroma Signatures Across Eight Chinese Sheep Breeds: Integrating Fatty Acid Composition, Volatile Profiles, and Aroma-Active Compounds

Breed-associated differences in roasted-lamb flavour are often described from volatile profiles alone, whereas the links among lipid precursors, volatile abundance and olfactory activity remain less clear. Here, fatty acid profiling, headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) and gas chromatography–olfactometry–mass spectrometry (GC–O–MS) were combined to compare eight Chinese sheep breeds under standardised roasting conditions, although rearing conditions differed among groups. Major unsaturated fatty acids, particularly C18:1n-9, C18:2n-6, C18:3n-3 and C20:4n-6, differed markedly among breeds. Aldehydes and pyrazines dominated the roasted volatilome, but their relative contributions varied. GC–O–MS revealed a shared roasted/nutty aroma backbone, with 2,3-dimethylpyrazine detected across all breeds, whereas lipid-derived odorants including hexanal, nonanal, octanal, (E)-2-octenal and 1-octen-3-ol showed greater breed-associated variation. Some breeds exhibited pyrazine-dominant profiles, whereas others showed greater contributions from lipid-derived aldehydes and alcohols. Unsaturated fatty acids were more closely associated with lipid-derived volatiles than with pyrazines. These findings indicate that breed-associated differences in roasted-lamb aroma are characterised mainly by shifts in the relative contribution of lipid oxidation products and Maillard-derived odorants against a shared aroma-active background.