Abstract
To evaluate the effects of roasting and varietal differences on pine nut flavour, an electronic nose, HS-SPME-GC-Orbitrap MS, and non-targeted metabolomics were used to compare the volatile profiles and metabolomes of raw and roasted Pinus pumila (PP) and Pinus koraiensis (PK) nuts. Roasting markedly amplified the metabolic and flavour differences between the two species. In PK, roasting activated pantothenate and CoA biosynthesis, promoting lipid oxidation and the formation of lipid-derived aldehydes that contributed to a pronounced fatty aroma. In contrast, PP exhibited greater metabolic stability, with flavour formation primarily driven by the Maillard reaction, resulting in pyrazine accumulation and balanced nutty notes. 4,5-epoxydec-2(trans)-enal was identified as the principal aroma-active compound. Molecular docking indicated favourable binding of key odourants to the olfactory receptors OR51E1 and OR5K1. These findings elucidate species-specific flavour formation mechanisms and provide a theoretical basis for optimising roasting strategies for different pine nut varieties.