Identification of key aroma-active compounds in sesame oil from microwaved seeds using E-nose and HS-SPME-GC×GC-TOF/MS.

The study investigated the volatile compounds of sesame oil and the effects of microwave processing (0-8 min with 1-min intervals), mainly focusing on the integral flavor characteristics and individual aroma-active compounds. A total of 82 characteristic odors were identified using GC×GC-TOF/MS. Fifteen volatile compounds with the highest odor activity values (OAV > 100) were selected as the key odors contributing to the flavor profile of microwaved sesame oil, including 2-methyl-propanal (pungent, malt, green), 2-methyl-butanal (cocoa, almond), furaneol (caramel), 1-octen-3-one (mushroom), 4-methyl-3-penten-2-one (sweet), 1-nonanol (fat, citrus, green), 2-methyl-phenol (phenol), 2-methoxy-phenol (smoke, sweet), 2-methoxy-4-vinylphenol (clove, curry), 2,5-dimethyl-pyrazine (cocoa, roasted nut, roast beef), 2-furfurylthiol (coffee, roast), 2-thiophenemethanethiol (sulfur), methanethiol (gasoline, garlic), methional (cooked potato), and dimethyl trisulfide (fish, cabbage). The OAVs significantly increased with a longer microwave process. Meanwhile, PCA results based on E-nose and cluster analysis results based on GC×GC-TOF/MS were similar to distinguish flavor formation during the microwave process. PRACTICAL APPLICATIONS: Sesame oils were prepared by a microwave process. Aroma-active compounds with the highest OAVs in sesame oils were not clear. Identification of key aroma compounds of sesame oils could adopt a comprehensive assessment method in combination with E-nose and individual odors detection. Microwave pretreatment as a new processing technology for sesame oil extraction could reduce the time consumption and produce a unique fragrant flavor compared to the traditional roasting process.