Volatile Metabolites of Goat Cheeses Determined by Ion Mobility Spectrometry. Potential Applications in Quality Control

Abstract

Headspace sampling coupled with multi-capillary column-ion mobility spectrometry (HS-MCC-IMS) has been used for extraction and identification of some volatile metabolites from different types of goat cheese samples. The only manual operation carried out in this method was the introduction of samples into vials; the following steps (headspace generation, injection of the volatiles compounds into MCC and IMS detection) were fully automated. The analysis by MCC-IMS allowed rapid and simple differentiation of goat cheeses made with raw and pasteurized milk. MCC-IMS produced multidimensional ion mobility spectra with different retention times and intensity information different for some individual metabolites. A total of six metabolites were identified in goat cheeses including 1 alcohol (1-hexanol), 1 ketone (2-nonanone), 2 aldehydes (octanal, trans-2-heptanal) and 2 esters (ethyl butanoate and propyl butanoate). Furthermore, the evolution of one targeted metabolite (ethyl butanoate) was monitored through different ripening times (60, 150, 180, 210, 240, 270 days). These preliminary results showed that this volatile compound increased during cheese ageing according to biochemical and microbial dynamic of the matrix, and therefore ethyl butanoate could be a potential marker of ripening time in these kinds of cheese samples. Therefore, the method could be used for quality control purposes in goat cheese producers.