Accelerated ripening of reduced fat semi-hard cheese from a mixture of cow's, goat's and ewe's ultrafiltrated milk by using a Lac- Prt- strain of lactococci

Abstract

The technological process for a reduced fat (360 g/kg total solids) semi-hard cheese, based on a mixture of cow's, ewe's and goat's milk concentrated by ultrafiltration, was assayed using starter cultures designed to accelerate proteolysis and improve flavour and aroma development. The proteolytic fractions studied (noncasein nitrogen, nonprotein nitrogen and amino nitrogen) were significantly higher in the cheeses elaborated with the selected starter (IFPL) towards a commercial starter (Flora Danica). The addition to the IFPL starter of a Lactococcus lactis subsp lactis Lac- Prt- strain (T1) caused, at the end of the cheese ripening time (3 months), a two-fold increase in the amino nitrogen content, when compared to the cheeses elaborated with the commercial starter. The reduced fat ultrafiltrated (UF) milk cheeses elaborated with IFPL starter achieved an adequate proteolysis together with the right balance of flavour and aroma. By using a starter culture previously selected for semi-hard cheeses, and enhanced by addition of Lac- Prt- lactococci, it was possible to accelerate in 1 1/2 months the ripening time required for the UF cheeses made with a commercial starter.