SUWARI AND KAMABOKO SARDINE GELS - EFFECT OF HEAT-TREATMENT ON SOLUBILITY OF NETWORKS

Suwari (set) and kamaboko (set and cooked) gels made with sardine surimi were prepared at normal heat-setting (35 or 40 degrees C) and modori (60 degrees 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 degrees 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 degrees C. However, MHC bands were visible when disulfide bridges were disrupted in gels set at 60 degrees C and in kamaboko gels set at 35 degrees C. This means that the structure of the set gels was altered at cooking temperatures when the kamaboko network was formed.