Changes of Volatile Flavor Compounds in Different Parts of Tricholoma matsutake during Shelf Life Analyzed by Electronic Nose Combined with Gas Chromatography-Ion Mobility Spectrometry

In order to investigate trends in the odor profiles of different parts (cap and stipe) of Tricholoma matsutake during the shelf-life, the present study used an electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) combined with principal component analysis (PCA) and cluster analysis to analyze the changes of volatile flavor substances in T. matsutake at different points of the shelf-life. The results showed that a total of 48 volatile organic compounds (VOCs), including 10 aldehydes, 6 alcohols, 5 ketones, 4 sulfur-containing compounds, 9 esters, 2 acids, 3 alkenes, 9 other volatile substances such as heterocyclic compounds, and 15 unidentified volatile compounds, were detected. The stipe contained a richer variety of volatile substances than the cap. In general, the types and contents of volatile substances in T. matsutake continued to decrease during the shelf-life period. The inflection point of volatile substances occurred after around 24 h for the cap, and after both around 12 and 48 h for the stipe. In conclusion, the combination of electronic nose and GC-IMS can be used to quickly and intuitively analyze the differences in volatiles between the cap and stipe of T. matsutake at different time points of the shelf-life, thereby helping to determine the freshness of T. matsutake.