Using ion mobility spectrometry for screening the autoxidation of peanuts

•An IMS configuration using the technique of constant RIP was established.•It was possible to identify oxidised peanuts by IMS without upstream equipment.•Hexanal showed two distinct peaks, correlated with autoxidation progress of peanuts.•A rapid screening of peanuts with respect to quality seems possible.

Autoxidation is a critical process in many fat containing foods that leads to reduced palatability because of the formation of off-flavour compounds. The aim of the study was to evaluate the applicability of ion mobility spectrometry (IMS) for detecting volatile off-flavour indicators from roasted peanuts which were subjected to storage at elevated temperature. IMS measurements were carried out using a sample inlet system that allowed to keep the reactant ion peak constant. It is evident from the ion mobility spectra that the level of autoxidation significantly affects the signal intensities in particular drift time regions. Supported by the IMS measurement of pure hexanal, and by qualitative analysis for volatile aldehydes and organic acids, the IMS peaks at relative drift times of approx. 1.7 have a large potential for being used as rancidity indicators.