In comminuted meat products the gel-forming abilities of the myofibrillar proteins are of major importance. In meat emulsions fat will be present in globules which are stabilized by a membrane coating made of salt-soluble proteins. These discontinuous fat particles act as fillers or co-polymers and stabilize the protein network. Differences in the physicochemical properties of saturated and unsaturated lipids affect the distribution of fat and thereby the functionality and quality of the final product. The objectives were to study the effects of lipid type and heat treatment on changes in microstructure of meat emulsions by use of a novel quantitative application of absorption- and phase-contrast tomography. The non-invasive technique offered the possibility to study the same sample in both raw and cooked condition. The samples were raw and heat treated meat emulsions (10% protein, 25% fat, 60% moisture) prepared with either pork fat or sunflower oil. The tomograms were obtained at a synchrotron facility using a grating interferometer which measured three different properties in the sample simultaneously: The attenuation length, the electron density and the diffusion length. Phase contrast imaging of the tomograms were used to analyse the impact of lipid type on spatial fat distribution, microstructure of the protein network and structural changes caused by heat treatment. The tomograms showed that the fat distribution in the meat emulsions depended on the physicochemical properties of the added fat. Use of vegetable oil resulted in homogeneous emulsions with smaller fat globules compared to the use of pork fat. This has previously been shown by the use of light micrographs. However, with the use of phase contrast imaging it was, from the same image, possible to resolve the protein phase to obtain information about the quality of the protein network and of the changes in microstructure caused by heat treatment. Further it was possible to compare the amounts of cooking loss from the emulsions. In conclusion phase contrast imaging with its high spectral resolution offers a unique possibility for studies of microstructure and is superior to histology since the information is obtained for the full volume.
|Title of host publication||InsideFood Symposium : Book of Proceedings|
|Number of pages||5|
|Publication status||Published - 2013|
|Event||InsideFood Symposium - Leuven, Belgium|
Duration: 9 Apr 2013 → 12 Apr 2013
|Period||09/04/2013 → 12/04/2013|