Investigation on proteolysis and formation of volatile compounds of Lighvan cheese during ripening.

The volatile compounds and protein profiles of Lighvan cheese, (raw traditional sheep cheese) were investigated over a 90-days ripening period. Solid-phase microextraction-gas chromatography-mass spectrometry [SPME-GC-MS] and sodium dodecyl sulfate polyacrylamide gel electrophoresis [SDS-PAGE] were used to identify volatile compounds and assess proteolysis assessment, respectively. Ripening breakdown products viz., acids (butanoic acid, 3 methyl butanoic acid, hexanoic acid, octanoic acid, decanoic acid,…) comprised of the highest number of detected individual compounds (10) followed by esters (9), alcohols (7), cyclic aromatic compounds (6), ketones (5) and aldehydes (4). Carboxylic acids were the dominant identified group; their levels increased during ripening and involved 48.22 % of the total volatile compounds at the end (90 days) of ripening. Esters, ketones, cyclic aromatic compounds and aldehydes also increased, whereas the alcohol content slightly decreased towards the end of the ripening. Degradation of β- and αS- casein was higher during the initial stage of ripening (1st month) of ripening than at later stages, which could be related to the inhibitory effect of salt on some bacteria and proteolytic enzymes.