Analysis of aroma components of red sour soup from main producing areas of Guizhou using electronic nose combined with HS-SPME-GC-MS

The volatile flavor components of the red sour soup were determined by electronic nose and headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The color parameters of the red sour soup were detected by colorimeter, and the model was constructed using orthogonal partial least squares-discriminant analysis (OPLS-DA) to study the aroma composition and differences of red sour soup samples from main producing areas of Guizhou. Key flavor substances (OAV>1) and key differential flavor substances (OAV>1 and VIP>1) were screened based on odor activity value (OAV) and variable importance in the projection (VIP) value. The results showed that there were significant differences in L* value, a* value and b* value of 4 red sour soup samples (P<0.05). The electronic nose analysis results showed that the 4 red sour soup samples had similar flavor profiles, but their volatile flavor compounds were different, and the electronic nose response values for sulfides and aromatic compounds were the highest. Principal component analysis (PCA) and linear discriminant analysis (LDA) based on electronic nose response values could effectively distinguish red sour soup samples from different producing areas. A total of 132 volatile flavor compounds in 4 red sour soup samples were detected by HS- SPME-GC-MS, among them, 26 aroma compounds were shared by 3 or more red sour soup samples. 9 key flavor substances and 2 key differential flavor substances were screened from red sour soup samples.