Volatile metabolite profiling of malt contaminated by Fusarium poae during malting

A volatile metabolite-profiling approach based on solid-phase microextraction (SPME) combined with gas chromatography–mass spectrometry was used to investigate volatile metabolic changes over the course of a malting process contaminated by Fusarium poae to assess its influence on malt flavor. GC–MS analysis of time-serial samples revealed a broad spectrum of volatile compounds including aldehydes, ketones, alcohols, organic acids, aromatics and furans. Statistical assessment of the data via principal component analysis demonstrated that at the initial phase of germination, the influence of F. poae was relatively small. However, its influence increased over time, resulting in differences between contaminated and controlled samples at 120 h and 144 h. Analysis of the corresponding loadings showed that volatile metabolites from green malt were influenced by contamination with F. poae fungi during malting to an extent, especially for the volatile aldehyde fractions. These compounds can be formed during both primary and secondary metabolism, and the potential exists for metabolic perturbation resulting from F. poae.