Texture and microstructure of low-fat Swiss chees

The objective of this study was to improve the textural properties of low-fat Swiss cheese. The first two sections focused on the evaluation of analytical methods for the textural and microstructural analysis of Swiss cheese. The last section was devoted to the improvement of low-fat Swiss cheese texture, through the modification of processing changes.;To determine the reliability of TPA tests, the Coefficient of Variation (CV) for each TPA parameter was closely investigated. Different microscopic methods were evaluated to determine the simplest that would clearly differentiate the structure of full-fat and low-fat Swiss cheeses. Thin-section and freeze fracture Transmission Electron Microscopy (TEM), and Confocal Laser Scanning Microscopy (CLSM) were evaluated. To improve the textural properties of low-fat Swiss cheese, the manufacturing procedures were modified by incorporating the homogenization of cream, lecithin and an emulsifying salt into cheese processing either individually or in combination.;Hardness and Young's modulus produced less than 10% CV at 25 and 50% compression. At 75% compression, the CV of them was at the range of 10-20%. The use of Hencky's strain minimized the effect of % compression and provided a greater significance to the differences in full-fat and low-fat Swiss cheeses. Both TPA hardness and Young's modulus showed statistically significant differences between full-fat and low-fat Swiss cheeses. Results indicated that low-fat Swiss cheese had harder texture and had a dense structure. Double staining CLSM, using Nile red and FITC, provided a way to identify the protein matrix, fat globules and voids in the structure by effectively differentiating fat globules from eyes or slits in Swiss cheese. CLSM made it possible to observe three-dimensional images of cheese. The combination of homogenization at 2500 psi, addition of 0.05% lecithin and addition of 0.05% emulsifying salt reduced hardness and Young's modulus by 31-57%. Sensory hardness correlated to instrumental measurements of hardness and Young's modulus. The softest low-fat cheese made in this study had significantly softer texture than low-fat control.