The evolution of volatile compounds profile of “Toscano” dry‐cured ham during ripening as revealed by SPME‐GC‐MS approach

Abstract

The volatile compounds profile is an important feature for the characterization of dry-cured hams. Some minor typical Italian products, such as 'Toscano' ham, have been poorly studied in regards to their composition of volatile compounds. In this article, we studied the evolution of the aromatic profile of 'Toscano' dry-cured ham by solid-phase microextraction-gas chromatographic-mass spectrometry (SPME-GC-MS) with ripening. Ten right thighs were cured according to the 'Toscano' PDO protocol, sampled at 0, 1, 3, 6 and 12 months and submitted to volatile compounds analysis by SPME with a Divinylbenzene (DVB)/Carboxen/Polydimethylsiloxane (PDMS) 75-µ Stable Flex fibre. An Agilent 5975C mass selective detector (MSD) spectrometer with electron ionization (EI) source operating in scan mode within the m/z 29-350 range was used for data collection. Seven internal standards, either deuterium labeled or absent in the specimens and chosen to represent low or high boiling esters, alcohols, acids or phenols, were added to the homogenized samples and used to normalize the SPME fibre response to account for response changes upon wearing. Linear calibrations were obtained in this way for selected representative compounds. Over 60 compounds belonging to esters, aldehydes, organic acids, ketones and alcohols were identified by comparison with spectral libraries and Kovats indices. Aldehydes were the most represented chemical family, followed by organic acids, alcohols, ketones and esters. The aldehydes and ketones increased during the first 3 months, when the larger formation of volatiles occurred. For other families, the evolution over time was less evident. The principal component and discriminant analyses of the aromatic profile were effective in classifying the hams at 0, 6 or 12 months of ripening while for 1 and 3 months' samples a partial overlapping was shown. These results represent the first characterization of 'Toscano' ham and may constitute the basis to identify the best ripening time and define an analytical quality standard for this typical ham.