Structural Analysis of the Aroma Compounds in the Chinese cabbage by Gas Chromatography Olfactometry Time-of-Flight Mass Spectrometry
Introduction
Aroma components in food, or “odor,” are key factors that influence palatability. These components include highly volatile compounds such as terpenes, esters, and alcohols, which combine in complex ways to create what we perceive as “aroma.” Aroma is not derived from a single compound but is a composite of numerous interacting substances, and their composition and concentration ratios determine the quality and uniqueness of food. Evaluating aroma components requires both sensory and chemical approaches. Gas chromatography-olfactometry (GC-O) is widely used for sensory evaluation of odor, while gas chromatography-mass spectrometry (GC-MS) is commonly employed for qualitative chemical analysis. Combining these techniques enables comprehensive understanding of food aroma, including sensory evaluation and detailed chemical profiling of unknown compound. GC-MS is extensively used for qualitative analysis of aroma and off-flavor compounds in food. Identification of aroma components by GC-MS typically relies on commercial mass spectral databases such as NIST. However, determining unknown aroma compounds that are not registered in these databases using GC-MS data alone has been challenging. In such cases, integrated analysis using a high-resolution time-of-flight mass spectrometer (TOFMS) combined with electron ionization (EI) and soft ionization methods allows determination of molecular formulas even for unknown substances. Furthermore, by employing msFineAnalysis AI, an automated structural analysis software equipped with a comprehensive structure prediction algorithm based on deep learning for mass spectral interpretation, it is possible to rapidly estimate structural formulas of unknown compounds. In this MSTips, we report the results of analyzing aroma components in pickled Chinese cabbage using headspace solid-phase microextraction (HS-SPME) combined with GC-O-TOFMS, followed by integrated analysis using msFineAnalysis AI.