Effect of high pressure and soy protein isolate combinations on the water holding capacity and texture of pork meat batters

Introduction. The used of high pressure and soy protein isolate combinations to emulsion meat products could improve the quality, water holding capacity, texture and increase product yield. Materials and methods. Raw pork batters were prepared as follows: 400g pork meat, 80g pork back-fat, 70g ice water, 10g NaCl; sample C2 had 10g soy protein isolate (2%); sample C3 - 20g soy protein isolate (4%). The vacuum packed batters were put into a high pressure vessel and were done with 200 MPa for 10 min at 10 +/- 2 degrees C. The texture profile analysis of cooked pork batters were carried out using a texture analyzer. Low field NMR relaxation measurements were carried out according in the NMR probe of a Niumag Pulsed NMR analyzer. Results and discussion. Compared with the C1, all the cooking yield of pork batters with various amount of soy protein isolate were increased significantly. The emulsifying activity of 11S globulins was much significantly improved at 200 MPa, that enhanced the water holding capacity of soy protein isolate. High pressure processing induced texture modifications have been used to affect myofibrillar proteins and their gel-forming properties, raising the possibility of the development of processed comminuted meat products. Over 200 MPa treatment, the protein extractability was decreased significantly in meat batters, and caused protein denaturation and/or aggregation, which limited their functionalities. The effects of relaxation time and peak ration of cooked pork batters by high pressure processing with different soy protein isolate were determined. There was three characteristic peaks in the cooked pork batters, which was named as T-2b, T-21 and T-22, respectively. T-2b is assigned to water tightly associated to protein and macro-molecular constituents, the relaxation population centered at approximately 0-10 ms in the cooked pork batters. The relaxation population of T-21 is centered at approximately 10-100 ms, which is a major component and considered to intra-myofibrillar water and water within the protein structure. Conclusion. The result of low field NMR exhibited that the batters with soy protein isolate had less water out the cooked pork batter and free water. Overall, the 2% soy protein isolate addition could improve the water holding capacity and texture of pork batters treated by high pressure.