Two flavors in adulterated sesame oil: Discovery, Confirmation, and Content Regularity Study

Gas chromatography-mass spectrometry (GC-MS) was utilized to identify the 5-(2-hydroxyethyl)-4-methylthiazole and γ-Nonanolactone in adulterated sesame oil. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was then employed for qualitative analysis of these flavors. A quantitative analysis method was successfully developed using methanol extraction and vanillin-D3 as an internal standard, with analyte recoveries ranging from 88.5–102.2% and relative standard deviations between 2.6% and 10.5% (n = 6). Subsequently, 31 batches of sesame oil from the market were tested, revealing that all samples contained the identified flavors within a relatively consistent range. However, some samples exhibited unusually high concentrations of these flavors, suggesting a potential risk of adulteration.