The Mechanisms of Setting and Modori during Heat-Induced Gelation of Fish Muscle Paste

点击翻译按钮获取中文摘要

The surimi-based products are produced through the thermal gelation of myosin as a major protein in the surimi with some modifications by setting and modori known as a degeneration or weakening of gel. Though, the mechanisms of the modifications have not been fully elucidated. In 1995, we revealed from the comparative studies on the setting of walleye pollack and salmon surimi pastes which were representatives for good and poor setting fishes that the setting is attributed to the modification of thermal myosin gelation by an endogenous transglutaminase (TGase) -catalyzed myosin cross-linking. Further studies were undertaken in 1996 to investigate the combined effects of myosin thermal gelation and TGase-catalyzed gelation during the setting gel formation. The gel forming ability of walleye pollack surimi was completely destroyed by the myosin denaturation and inactivation of the endogenous TGase. The addition of TGase into denatured surimi paste partially recovered the setting gel formability. On the other hand, no setting was induced in the native surimi paste without TGase activity. The addition of TGase also induced the setting gel formability into carp actomyosin paste, a non-setting species.Two different mechanisms for modori were demonstrated : (1) when myosin proteolysis occurs during setting prior to final cooking, the longer setting results in weaker cooked gels. (2) when the gelation precedes proteolysis, the gels once formed are degenerated. The polymers of myosin and its fragments formed by TGase-catalyzed cross-linking were identified upon SDS-PAGE.The modori induced by structural alternation of heated actomyosin is still under investigation.