Suwari and kamaboko sardine gels: Effect of heat treatment on solubility of networks

Abstract

Suwari (set) and kamaboko (set and cooked) gels made with sardine surimi were prepared at normal heat-setting (35 or 40°C) and modori (60°C) temperatures and treated with solutions breaking ionic bonds, hydrogen bonds, hydrophobic interactions, and disulfide bridges. The lower gel strength of the gels obtained at modori temperature corresponded to a higher solubility of these gels in solutions breaking hydrophobic interactions and disulfide bridges. For suwari gels set at 35 and 40°C more protein was solubilized when electrostatic interactions and hydrogen bonds were ruptured. SDS-PAGE showed a higher amount of actin in these two fractions. No myosin heavy chain (MHC) bands were observed in any of the fractions obtained from suwari gels heat-set at 35 and 40°C. However, MHC bands were visible when disulfide bridges were disrupted in gels set at 60°C and in kamaboko gels set at 35°C. This means that the structure of the set gels was altered at cooking temperatures when the kamaboko network was formed.