Federico Stilo;Erica Liberto;Nicola Spigolon;Giuseppe Genova;Ginevra Rosso;Mauro Fontana;Stephen E. Reichenbach;Carlo Bicchi;Chiara Cordero
The volatile fraction of hazelnuts encrypts information about: cultivar/geographical origin, post-harvest treatments, oxidative stability and sensory quality. However, sensory features could be buried under other dominant chemical signatures posing challenges to an effective classification based on pleasant/unpleasant notes. Here a novel workflow that combines Untargeted and Targeted (UT) fingerprinting on comprehensive two-dimensional gas-chromatographic patterns is developed to discriminate spoiled hazelnuts from those of acceptable quality. By flash-profiling, six hazelnut classes are defined: ,, ,, ,, ,-,, ,-, and , Chromatographic fingerprinting on composite 2D chromatograms from samples belonging to the same class (i.e., composite class-images) enabled effective selection of chemical markers: (a) octanoic acid that guides the sensory classification being positively correlated to mould; (b) ?-nonalactone, ?-hexalactone, acetone, and 1-nonanol that are decisive to classify OK and rancid samples; (c) heptanoic and hexanoic acids and ?-octalactone present in high relative abundance in rancid-solvent and rancid-stale samples.