Yield, thermal denaturation, and microstructure of proteins isolated from pale, soft, exudative chicken breast meat by using isoelectric solubilization/precipitation

An isoelectric solubilization/precipitation process was adopted to improve the functionalities of PSE chicken meat protein. The results compared the effects of two different recovery pH values (5.5 and 6.2) on the gelation properties of the proteins. A higher recovery pH significantly decreased the recovery yield (P < 0.05). The protein profile of the supernatant obtained by centrifugation showed a darker actin band upon recovery at pH 5.5 than that upon recovery at pH 6.2, thus indicating greater actin loss at pH 5.5. This actin loss also resulted in lower endothermic enthalpy of the actin peaks than those of the proteins recovered at pH 6.2. The endothermic transition peaks of myosin and actin shifted to lower (P < 0.05) temperatures than those of the control (CON). Gels made from the alkali-extracted proteins displayed a more uniform and compact porous network than those made from acid-extracted proteins. A higher recovery pH also contributed to a more regular and ordered structure. For the acid-extracted proteins, higher recovery pH resulted in significantly lower cooking loss (P < 0.05). Overall, the results demonstrated that protein recovered at pH 6.2 under the proposed alkaline process is a reliable alternative for improving the gelation properties of PSE meat protein.