Texture-modifying properties of microbial transglutaminase on 2 popular Hungarian products: Trappist cheese and frankfurter

The aim of this study was to show how microbial transglutaminase (mTG) can be used as an effective texture-modifier for two popular Hungarian products: Trappist cheese and frankfurter. In both cases we investigated how components of these products, milkfat in cheese and phosphate in frankfurter, can be substituted by mTG. Therefore, Trappist cheese samples were produced from cow milk of 2.8%, 3.5%, and 5% milk fat. The effect of ripening was evaluated with Texture Profile Analysis (TPA) and sensory evaluation (scoring test, 10 trained panellists). Springiness and cohesiveness values were significantly higher by enzyme-treated semi-hard cheese samples at lower milk fat levels. Sensory evaluation showed that the enzyme-treatment led to higher scores by cheese samples made from cow milk of 3.5% and 5% milk fat. Frankfurter was made with 0.1%, 0.3%, 0.5%, and 0.7% tetrasodium pyrophosphate, and partly enzyme-treated with 0.2% commercial mTG enzyme preparation. Our results showed that mTG is able to significantly improve hardness and crunchiness by frankfurters made with 0.1% phosphate addition. Our sensory evaluation suggests that mTG and phosphate should be applied in combination in order to have a final product with recognisably more homogeneous texture

Changes of protein profiles in pork and beef meat caused by high hydrostatic pressure treatment

In the experiments pork loin and beef sirloin were treated by pressures of 100 to 600 MPa by 100 MPa steps for 5 min. Colour changes of samples and the changes of proteins were investigated. The latter were examined with isoelectric focusing and SDS polyacrylamide gel electrophoresis. We found that myoglobin behaved completely differently in case of the two different species. Myoglobin has mostly lost its native state at 300 MPa pressure in case of pork, but the beef myoglobin could remain native even up to 500 MPa. The treatment at 300 MPa or higher pressure values caused almost complete aggregation and denaturation in case of pork and beef proteins. The results of SDS-PAGE and the colour measurement confirmed this finding