Characteristic volatiles analysis of Dongbei Suancai across different fermentation stages based on HS-GC-IMS with PCA

Volatile flavor compounds determine the holistic, unique, sensory characteristic of fermented food. The characteristic volatiles across the fermentation process of Dongbei Suancai (DS) were investigated by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with principal component analysis (PCA). A total of 19 representative flavor substances were identified in the samples. The differences of volatiles in naturally and inoculated-fermented DS from different fermentation stages were detected. Ethyl acetate, ethyl butanoate, ethyl 3-methyl butanoate, acetone, butanone, 2, 3-butanedione, and dimethyl disulfide are important volatile substances in DS, which were all found to be formed in the prophase of fermentation. As fermentation proceeds, inoculated DS showed an improved flavor with ester aromatic substances becoming enriched, including propyl bytanoate and ethyl hexanoate. Furthermore, inoculated fermentation leads to a typical component, namely 3-methylbutanol, being generated after the addition of Lactobacillus Plantarum LND 399 as a starter. The PCA was subsequently conducted based on the signal intensity of the identified volatile substances and showed that DS samples were distinguished favorably in mutually independent comparative spaces. This study revealed that the combination of HS-GC-IMS and PCA is an effective tool for analysis of the characteristic volatiles in DS samples. PRACTICAL APPLICATION: This study has shown that the combination of HS-GC-IMS and PCA is an effective tool for analysis of the characteristic volatiles in DS samples. This will provide a useful method for the identification and classification of DS flavor.