Optimization of an intra-oral solid-phase microextraction (SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC-TOFMS) method for oral aroma compounds monitoring of Baijiu

The ‘‘after-odor” is essential to the quality and consumer preference of Baijiu. An intra-oral solid-phase microextraction (SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC-TOFMS) was developed for oral aroma compounds monitoring of Baijiu. The extraction time, sip volume and rinse time were 120 s, 5 mL, and 10 s, respectively. The procedure showed good performances at concentrations of 1.56 μg/L–1500 mg/L for different aroma compounds of Baijiu (most R2 > 0.9). Furthermore, the optimized procedure detected 85 aroma compounds with different chemical structures and provided good representations of the light, strong, soy sauce and mix aroma type Baijiu’s oral aroma profiles. Principal component analysis’s (PCA) cumulative interpretation rate was 72.42%. The acceptable performance of this procedure can be combined with dynamic sensory evaluation to improve the quality of the Baijiu aroma.