Study of the biochemical changes during ripening of Ahumado de ءliva cheese: a Spanish traditional variety

The changes in chemical composition, main physico-chemical parameters, classical nitrogen fractions, caseins and their degradation products, and some fat characteristics were studied during the ripening of ten batches of Ahumado de Áliva cheese, a traditional variety made in the north of Spain. The values of the different compositional and physico-chemical parameters at the end of the ripening did not differ significantly from those found in other cowsʹ milk cheeses elaborated by similar technology. The low pH values are outstanding. The presence of residual lactose at the end of ripening is also relevant. Total soluble nitrogen and non-protein nitrogen increased very little during ripening. The evolution of the values of the different nitrogen fractions show that this cheese undergoes very little proteolysis and that the rennet is the main proteolytic agent. Using PAGE, it was possible to show that, throughout ripening, only 22% of αs-casein and 9% of β-casein were degraded. The TBA value indicated that the fat of Ahumado de Áliva cheese does not undergo noticeable autooxidation during ripening. The acidity index of the fat also indicated that this cheese underwent little lipolysis during ripening.