Efficacy of fatty acids and terpenoids and weakness of electronic nose response as tracers of Asiago d'Allevo PDO cheese produced in different seasons

The goal of this study was to verify the suitability of using fatty acids (FAs), terpenoids, and electronic nose response as potential tracers of the seasonal variations in Asiago d’Allevo PDO cheese. Cheese samples produced during the early and late summer grazing and the autumn/winter indoor seasons were compared. Based on their FA composition, the early and late summer cheeses were almost completely indistinguishable from each other. However, they both demonstrated higher quality when compared to the autumn/winter cheeses, showing lower levels of hypercholesterolemic saturated FAs (C12, C14, and C16) and higher levels of total mono- and polyunsaturated FAs, oleic (C18:1 c9), trans-vaccenic (C18:1 t11), rumenic (C18:2 c9t11), and α-linolenic (C18:3 c9c12c15) acids. Among terpenoids, camphene, cedrane, and total sesquiterpenoids were able to differentiate the cheeses manufactured during the three periods of production. Moreover, α-pinene, α-thujene, β-pinene, δä-3-carene, myrtenol, dihydrocarveol isomer 1, and unidentified sesquiterpene 1 distinguished the late summer cheeses from those obtained in the other two seasons. Principal component analysis of electronic nose data showed that the Asiago cheese samples were widely dispersed in the score plot and no clear clusters appeared evident. Furthermore, cross-validated linear discriminant analysis of the electronic nose data showed unsatisfactory classification performance (53.8%) regarding the period of production. Our results showed that coupling FAs and terpenoids information could be a suitable method for tracing Asiago d’Allevo PDO cheeses according to their season of production. However, no reliable information at this level seemed to be obtainable from the electronic nose response.