Evolution of volatile compounds and physical, chemical and sensory characteristics of Toscano PDO ham from fresh to dry-cured product

Abstract

Physical and chemical changes in Toscano ham lean were evaluated according to three different seasoning time (14, 16 and 18 months). Moreover, on Semimembranosus muscle, the volatile profile at 0, 1, 3, 6, 12, 14, 16 and 18 months of seasoning was determined by SPME–GC–MS. Eventually, a quantitative-descriptive sensory evaluation was performed. Longer seasoning times led to a decrease of Chroma in Biceps femoris, and also protein and proteolysis index decreased as the seasoning time increased. A total of 97 volatile compounds (VOCs) belonging to seven chemical families (29 aldehydes, 16 esters, 14 alcohols, 13 hydrocarbons, 12 ketones, 10 acids, 2 furans and 1 nitrogenous compound) were identified. Sensory evaluation outlined the major differences between 18th months ham and the other two classes, with the former being harder and with a slight presence of off flavor and off odor. The VOCs evolution during curing was studied and a multivariate approach was performed to test the feasibility of using the VOCs profile to predict the curing stage of Toscano ham. The discriminant analysis successfully managed to separate the samples of 0–6 months from the ones of 12–18 months using 26 of the identified VOCs. Among them, pentane 2,3-dimethyl, acetophenone and 9-decenoic acid were strong discriminants for 0–6 months hams, while dodecanoic, benzeneacetaldehyde, 3-octen-2-one and pentanoic acid ethylester were linked to 12–18 months hams. Within the high maturing classes (12, 14, 16, 18 months of seasoning), the 17 discriminating compounds identified successfully allocated only 12 and 18 months samples. The main VOCs associated with the “12 months” class were nonanal, 1,5-diphenyl-3-methylthio-1,2,4-triazole and 6-methoxy 2-hexanone. The “18 months” seasoning class, instead, was identified by 1,5-diphenyl-3-methylthio-1,2,4-triazole, phenol and l,2-butoxy ethanol.