Identification of Key Aroma-Active Compounds in Plum, Jujube, and Grape Extracts via GC×GC-O-TOF-MS, GC-MS, Aroma Recombination and Omission Tests

Fruity natural flavors are widely used in food, cosmetics, and tobacco products, and their flavor profiles directly affect the sensory quality of the final products. However, the volatile organic compound systems in these flavors are highly complex, and severe co-elution among volatile components makes effective component resolution a persistent analytical challenge. In this study, comprehensive two-dimensional gas chromatography–olfactometry–time-of-flight mass spectrometry (GC×GC-O-TOF-MS) was employed to separate and identify volatile odor compounds in three natural fruit flavor extracts: plum, jujube, and grape. A total of 113, 103, and 85 volatile odor compounds were identified from the plum, jujube, and grape extracts, respectively. By progressively adjusting the split ratio, aroma extract dilution analysis was performed, leading to the screening of 14, 11, and 32 aroma-active compounds from the three extracts, respectively. Compounds with high flavor dilution factors were subjected to quantitative analysis, and their odor activity values were calculated. Subsequently, omission and recombination experiments were conducted to confirm the key aroma-active compounds in each extract. The results showed that octanal was a key aroma compound shared by the plum and jujube extracts, while ethyl cinnamate was common to both the plum and grape extracts. Through a molecular sensory science approach and utilizing GC×GC-O-TOF-MS chromatographic separation technology, this study provides a reliable analytical platform for aroma characterization in complex samples. It also establishes a critical theoretical and data foundation for precisely identifying key aroma-active components and implementing targeted aroma modulation to enhance the natural flavor quality of fruits.