Rheological, textural and sensory characteristics of high-pressure treated semi-hard ewes' milk cheese

High-pressure (HP) processing was investigated for determining potential changes induced on textural, rheological, sensory and compositional characteristics of semi-hard ewes' milk cheeses. Pressures from 200 to 500 MPa were applied at day 1 or day 15 after manufacture. Applying pressure on the first day after cheese manufacture caused an increase in pH and also increased the retention of remaining water into the curd after HP treatment. Applying pressure on day 15 of ripening led to chesses with characteristics more similar to control cheeses. Different behavior on mechanical characteristics was observed depending on the pressure conditions applied. Moderate pressures (200 and 300 MPa) enhanced the firming of cheeses, which was demonstrated in the increase of fracture stress and G* values. The highest conditions of pressure applied, especially 500 MPa, produced a weakening effect in the casein matrix. These cheeses showed the highest deformability and the lowest fracturability and rigidity. The sensory panel also found this treatment to produce the softest, less elastic and less crumbly cheeses. On the other hand, cheeses treated by HP at day 15 were similar to the control and preferred by the panel. (c) 2006 Elsevier Ltd. All rights reserved.