Formation of characteristic aroma compounds in walnut kernels during thermal processing and their potential recognition by human olfactory receptors

L.) is an oil-rich nut valued for its nutritional quality and characteristic flavor. Different thermal processing methods, including roasting, microwave treatment, and stir-frying, may shape walnut sensory perception by altering the composition and abundance of key aroma compounds and thereby influencing their differential interactions with human olfactory receptors. However, these relationships remain insufficiently understood. Here, walnut aroma under different thermal treatments was investigated using HS-SPME-GC-MS, sensory evaluation, electronic nose analysis, and high-throughput molecular docking. A total of 54 volatile compounds were identified, and thermal processing markedly promoted the formation of pyrazines, aldehydes, and some furans. Roasted samples showed the strongest nutty and roasted attributes and the highest acceptability. Correlation analysis indicated that pyrazines were closely associated with nutty and roasted notes, whereas some lipid oxidation-derived aldehydes and alcohols were related to fatty and green notes. Docking identified OR2AK2, OR11H2, and OR2G2 as candidate receptors.