Influence of the making and ripening processes on the plasmin activity of argentinean cheeses

FERNANDEZ, V.; CANDIOTI, M.; PEROTTI, M.C.; BERNAL, S.; ZALAZAR, C.

Scienza e Tecnica Lattiero-Casearia

Associazione Italiana Tecnici del Latte

Lugar: Parma, Italia; Año: 2006 vol. 57 p. 25 - 41

Plasmin is the main indigenous proteinase in milk and plays and important role in cheese ripening. This enzyme is part of a complex system including the active enzyme (plasmin), its inactive predecessor (plasminogen), a plasminogen activator and two inhibitors. Modifications in plasmin activity in cheese can be produced by differences in the productions technology and during the ripening process. The objective of this study was to determine the plasmin and plasminogen activities in Argentinean cheeses. Fourteen commercial cheese samples from different varieties and three samples of Reggianito Argentino produced in our plant, were analyzed. A colorimetric method was employed for quantification of plasmin and plasminogen activities. The degradation of caseins during ripening was followed by Urea-Page. An important difference in enzyme activity was observed in relation to technology of production. In this way, soft and very soft cheeses showed the lowest plasmin activity whereas hard cheeses showed the highest activity. Plasmin activity increased during ripening of Reggianito Argentino cheese. On the other hand, a positive correlation was found between plasmin activity and the degradation level of beta-casein.