Monitoring alkyl pyrazines in roasted hazelnuts by SHS-GC-IMS: IMS response assessment and standardization

Gas chromatography coupled with ion mobility spectrometry (IMS) is an analytical tool which is rapidly becoming widespread in the analysis of food volatiles. Despite this increasing popularity, an assessment of the IMS response for several flavor compound classes is not yet available. This study focuses on alkyl pyrazines and their determination in roasted hazelnut pastes. These Maillard reaction products are crucial to determine the aromatic profile of roasted foods and are suitable markers for industrial roasting monitoring. The instrumental response of 8 alkyl pyrazines was studied using a model matrix and a matrix matching approach. The results showed a relevant effect of the pyrazine ring substitution pattern on the concentrationresponse curve trends, highlighting that an external standardization of the IMS response is required to make possible relative abundance comparisons between analytes. A response standardization was therefore developed and applied to determine alkyl pyrazines in samples with different roasting intensity and geographical and botanical origin.

Automated summary

Gas chromatography coupled with ion mobility spectrometry (IMS) is a useful tool for analyzing food volatiles. This study focused on the determination of alkyl pyrazines in roasted hazelnut pastes, which are crucial for determining the aroma profile of roasted foods. The results showed that the substitution pattern of the pyrazine ring had a significant effect on the concentration-response curve trends, highlighting the need for external standardization of the IMS response.