Changes in the Physical Properties and Composition of Fish Bone Cured in an Acetic Acid Solution

Abstract

Changes in the physical properties and composition of fish bones were examined after curing in an acid solution to provide data for their better utilization. Raw or steamed fish bones from horse mackerel were cured in a 4 % acetic acid solution for 120 h. Their breaking strength was measured with a rheometer, and the inorganic components were measured by ICP-AES. When the fish bones had been cured in acetic acid, the maximum force needed to break the bone decreased rapidly up to 1 h of curing and thereafter continued to decrease up to a curing time of 120 h. Curing in acetic acid decreased the weight and diameter of the centrum, and increased its water content, which implies a compositional change to the fish bone by curing. Little protein was eluted from the fish bone, but minerals were rapidly eluted with increasing curing time in acetic acid. Horse mackerel bones were quickly softened by curing in acetic acid, which can probably be explained by the elution of bone minerals into the acidic solution. While the steamed fish bones required a shorter period for softening than the raw fish bones, the elution of inorganic components was less in the former.