Gel-forming properties and their seasonal changes of freshwater fish surimi

According to the three-dimensional contour maps showing the gel-forming properties of surimi, 8 freshwater fish species surimis were classified into two types. The V-valley type surimi (silver carp, big-head carp, Chinese snake head and blunt snout bream) shows easy setting, low resistance to gel collapse, high enhancement ability with two-step heating, and narrow optimum heating temperature and time area, which are the same characteristics as walleye pollack surimi. In contrast, the Plateau type surimi (tilapia, grass carp, mud carp and common carp) illustrates difficult set, high resistance to gel collapse, no enhancement ability with two-step heating, and wide optimum heating temperature and time area. There are seasonal changes of gelling properties of silver carp surimi, and the setting ability of surimi gel is higher in winter and lower in summer. In addition, thermal stability of myofibrillar protein from silver carp surimi is higher in summer and lower in winter. Therefore, the setting ability of surimi gel is evidently affected by thermal stability of myofibrillar protein of surimi, that is, the larger the inactivation rate of myofibrillar protein, the higher the gelation rate of setting.