Characterizing the key aroma compounds of barley malt from different origins using GC-E-Nose, HS-SPME-GC-MS, and HS-GC-IMS

The origin of malt is a crucial factor influencing malt flavor. In this study, the volatile compounds of barley malt from four different producing areas were comprehensively characterized by gas chromatography electronic nose (GC-E-Nose), gas chromatography-mass spectrometry (GC-MS), and gas chromatography ion mobility spectrometry (GC-IMS). GC-E-Nose analysis revealed significant differences in volatile flavor compounds among malt samples from different origins. GC-MS identified 71 volatile compounds, with aldehydes being the most abundant in all four samples. GC-IMS identified 50 volatile compounds, and obtained the most abundant aldehydes included butyraldehyde, 3-methyl-2-butyraldehyde. etc not detected by GC-MS. The combination of GC-MS data with odor activity value (OAV) analysis identified 24 flavor compounds as key aroma compounds (OAV ≥1). Partial least squares discriminant analysis (PLS-DA) model combined with one-way analysis of variance (ANOVA) was used to screen out seven volatile markers: 1-penten-3-ol, decanal, ethyl butyrate, ethyl acetate, ethyl isovalerate, isoamyl acetate, and dimethyl sulfide. The integration of these techniques provided a better characterization of flavor compounds and their differences in malt from different origins. The results provided theoretical guidance for the factory to improve malt flavor quality.