Comparison Of Functional Properties Of Pse-Like And Normal Chicken Meat

During meat processing, functional properties of muscle protein exhibited in three major respects, protein solubility, gel characteristic and emulsifying properties. It was necessary to extract the functional components, such as myofibrillar proteins, in further processed products. The amount of protein extracted and the interactions between these proteins and water, fat and themselves played an important role in holding water and fat, forming specific flavor and texture. Chicken breast meat was one of raw meat used frequently in processed meat product. However, there was a certain proportion of PSE-like meat existed in chicken, which was characterized by higher L*, lower pH, poor water retention capacity and partial protein denaturation. So it was important to learn the functional defects of PSE-like meat, and worked out ways to deals with it. In present study, PSE-like meat and normal meat were selected by pH24and lightness, following PSE-like meat L*>53, pH24<5.7; normal meat46<L*<53,5.7<pH24<6.1. And these two classes of meat were tested of protein extractability, gel properties and emulsifying characteristics. Also DSC, rheometer, and texture analyzer were used respectively to learn and compare the DSC thermogram, dynamic rheological properties and texture of normal and PSE-like meat. To study the WHC of PSE-like meat, both of these two classes of meat were tested of moisture uptake and cook yields by salt-induced swelling methods. And further their myofibrils were irrigated and observed with phase contrast microscope for more information of myofibril swelling.1Study of PSE-like and normal chicken meat in moisture uptake, protein extractability and denaturationNormal and PSE-like meat were tested of protein extractability, process of thermal denaturation with DSC, and also moisture uptake. The results indicated that compared with normal meat, PSE-like meat showed lower protein extractability among sarcoplasm protein, myofibrillar protein and total protein. Determination with DSC manifested that myosin and sarcoplasm from PSE-like meat denatured at lower temperature than that of normal meat, but their actins did the same way. PSE-like meat also showed lower moisture uptake and cook yield, higher pellet cook loss, and when pH was adjusted to that of normal meat, WHC of PSE-like meat was improved, but was still lower than normal meat, indicating partial restoration of protein functionality. Poorer WHC of PSE-like meat may be attributed to its lower pH and protein extractability, and thus do harm to product quality.2Comparisons of rheological properties and textural characteristics between PSE-like and normal chicken meatThere were significant differences in rheological properties, cook loss and textural characteristics between Ground PSE-like and normal meat. PSE-like meat showed a different gelation curve from that of normal meat, which was characterized by lower G" in both initial and end of heat treatment, and bigger tan8value. And also it was at lower temperature that PSE-like meat obtained certain inflexion points. PSE-like meat was also found of higher cook loss, but lower hardness, springiness, cohesiveness, chewiness and resilience. There is significant correlation between pH and L*of raw meat and rheological properties and textural characteristics of products, and lower pH and poorer WHC may be response for the difference.3Study of swelling index, solubility, gel and emulsifying properties from PSE-like and normal meatPSE-like meat characterized by low pH24and high lightness showed shorter sarcomeres than normal meat, decreased swelling index when irrigated with2%NaCl in the presence of TPP, and decreased solubility. There were significant differences in gel characteristics and emulsifying properties among normal and PSE-like meat. Gel made from PSE-like myofibril protein had smaller hardness (31%less) and lower water holding capacity (9%less). EAI of both PSE-like meat myofibril and sarcoplasmic protein were lower than that of normal meat, but there is no significant difference in ESI. All these indicated that PSE-like meat showed loss of functional properties in a certain degree.