RHEOLOGICAL AND MICROSTRUCTURAL CHARACTERIZATION OF DOUBLE CREAM CHEESE

Firmness at 5-degrees C, dynamic viscoelastic moduli (G', G'') and cap illary extrusion profiles at 20-degrees C, were obtained on double cre am cheese after the different steps of processing (curd obtention, mix ing at 70-degrees C and 500 r.p.m. with heat denatured WPC, heating at 85-degrees C, homogenizing at 20 MPa (1st stage) and 5 MPa (2nd stage ) and cooling to 20-degrees C and 13-degrees C) and storage 7-9 days a t 5-degrees c. It was found that double cream cheese became firmer and more elastic after heating and homogenization, although it became sof ter and more viscous after mixing and cooling. Transmission Electron M icroscopy (TEM) and cryo-Scanning Electron Microscopy (SEM) micrograph s showed that rheology results could be related to aggregation (during heating and homogenization) and disruption (during cooling) of milk f at globule/casein complexes. Dispersion of homogenization clusters aft er cooling, and aggregation of milk fat globules during storage caused double cream cheese structural instability to appear. It was suggeste d that the heterogeneity of capillary extrusion profiles could be quan tified through application of fractal concepts and Fourier analysis an d related to structure and texture of double cream cheese.