Studies on the mechanism of gel-reinforcing effect of starch in kamaboko-gel-I. Effect of heating temperature on structure and gel-reinforcing ability of starch granules in kamaboko-gel.

To clarify the mechanism of gel-reinforcing effect of starch in kamaboko, changes in physical properties of starch-containing kamaboko gels and structure of starch granules during heating were examined. Jelly strength of starch-containing kamaboko gels increased with a rise of heating temperature up to 90°C, and vice versa above 100°C. The gel-reinforcing effect of starch at 90°C varied with kind as follows: potato starch>wheat starch ?? orn starch>waxy corn starch≥high-amylose corn starch. This order did not varied, even if the heating temperature was risen to 120°C. The extent of decrease in jelly strength during heating at 120°C in non-starch containing kamaboko was smaller than in starch-containing kamaboko. A scanning electron microscopic observation revealed that potato starch having relatively strong gel-reinforcing effect was gelatinized thoroughly and swelled up at a heating temperature up to 90°C. The internal parts of the starch granules were observed to be completely disrupted by the heating process at a temperature above l10°C. However, the gel-reinforcing effcet brought about by starch remained even though the temperature of heating process was above 90°C where the structural disruption of starch granules was initiated. These findings suggested that the gel-reinforcing effect of starch might be largely attributable to concentration of surimi due to water absorption by starch granules.