Aroma and flavor profiling of walnut oils from five major Xinjiang cultivars: sensory evaluation and comparative analysis

Xinjiang has many walnut varieties, but none are specifically used for oil pressing. This study compared the extraction results of SPME and SDE, two sample preparation methods, for the flavor analysis of walnut oil from five varieties in Xinjiang. A multi-technique approach combining GC–MS, electronic nose, GC-IMS, and sensory evaluation was employed, and the walnut oil flavors were assessed through a correlation analysis of GC–MS data and sensory attributes. Sensory evaluation led to the development of a flavor wheel dominated by green, nutty, greasy, and roast attributes. Integrated analysis identified 47 volatile compounds across seven chemical classes, including aldehydes, ketones, pyrazines, and acids. Among these, 2,6-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, trimethylpyrazine, Octanal, (E,E) -2,4-decadienal, (E,E) -2,4-hexadienal, and 2-octanone were identified as key aroma contributors, closely associated with nutty and raw green notes. Among the five walnut oil samples, the evaluators showed a preference for the walnut oil prepared using Xin 2. These findings provide an initial exploration of the volatile compound composition and sensory characteristics of Xinjiang walnut oil, offering a reference for future research on the screening of walnut varieties for the development of flavored walnut oil. • Walnut oil had nutty, greasy, raw green, and roasted aromas in an aroma wheel. • Forty-seven volatile compounds were identified in pressed walnut oils from five cultivars. • Fifteen odor-active compounds (OAVs >1) defined nutty and green aroma characteristics. • ‘Xin 2’ walnut oil showed the highest sensory preference with stronger nutty and roasted notes.