CHARACTERISTICS OF SARCOPLASMIC PROTEINS AND THEIR INTERACTION WITH MYOFIBRILLAR PROTEINS

Abstract

The protein solubility and molecular-weight distribution of freeze-dried sarcoplasmic proteins (SPs) from rockfish treated under low and high pH as well as various NaCl concentrations were elucidated. The solubility of SPs was significantly suppressed at an acidic pH (2.0–4.0) and in the presence of high salt concentration (0.5 M NaCl). The least amount of protein was lost when SPs were treated at pH 2.0 or 3.0 followed by precipitation at pH 5.5. The interaction of SPs with Alaska pollock surimi (myofibrillar proteins) was also investigated. The addition of SPs appeared to delay the thermal denaturation of myosin and actin. The SPs positively contributed to the gelation of myofibrillar proteins as judged by breaking force.