Enzymatic evolution during ripening of Tallegio cheese related to the surface microflora
1998
Rossi, J. | Gobbetti, M. | Smacchi, E. (Agricultural Faculty of Perugia (Italy). Inst. of Dairy Microbiology) | Battistotti, B. | Fox, P.F.
The biochemical characteristics of Taleggio cheese during ripening were found to be related to the activity of the surface microflora. Analyses were conducted on the surface, middle and core layers of the cheese from three production batches. In the 42-day-old cheese there were high numbers of starter lactic acid bacteria and surface growth of yeasts (log 7.20 cfu per g) and moulds. A gradient of salt-in-moisture from the surface to the core persisted until about 21 days which influenced the growth of the cheese surface yeasts. A marked increase in pH was observed only on the cheese surface. Initially, the concentration of pH 4.6-soluble N was similar between the layers, but from 21 days onwards, hydrolysis was greater in the external region. No pronounced differences were observed in the proteolytic (peptidases and proteinase), esterolytic and lipolytic activities of the three cheese layers during the first 21 days of ripening but thereafter a marked gradient of the enzymatic activity was noted from the cheese surface to the core. Electrophoresis showed hydrolysis of alphas1- rather than beta-casein in all the cheese layers. RP-HPLC of pH 4.6-soluble, ethanol-soluble and -insoluble fractions showed that a small production of various sized peptides occurred before 21 days and greater hydrolysis was detected in the cheese surface. The ratio of volatile to non-volatile free fatty acids did not change during ripening. On the basis of these results a further biochemical characterization and selection of the yeasts isolated from the surface of Taleggio cheese is warranted.
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