Headspace-Gas Chromatography-Ion Mobility Spectrometry Provides New Insights into Aroma Differences and the “Increasing Fragrance over Time” Phenomenon of Lysimachia foenum-graecum Hance

Abstract

Lysimachia foenum-graecum Hance (LF) has a special fragrance due to its volatile components (VCs). However, this fragrance, which might be related to the changes in VCs and contents, is obviously disparate across LF samples from different storage times and regions. In order to investigate the differences in VCs of LF from different storage times and regions, a headspace-gas chromatography-ion mobility spectrometry technique was proposed and applied. The Gallery plots of different samples showed significant differences. According to the fingerprints, a total of 29 compounds with significant differences were identified. Furthermore, 1,8-cineole, 2-octanone, heptanal monomer, and 2-methylpropa might be the key components for origin identification, while phenylacetaldehyde, 2-ethylfuran, 2-pentyl furan monomer, gamma-butyrolactone monomer, and maltol might be the key components that make LF more fragrant after storage. Besides, the principal component analysis initial solution to original variables demonstrated that the two principal components accounted for 51 and 22% of the total variance, respectively. Similarity analysis showed the similarity within the individual groups was above 90% excluding 1A and 2E, while it was only 60 to 70% between the groups. The research results provide a non-destructive method without pretreatment for LF from different origins and different storage times and also provide a scientific basis for the application of LF.