Relationship between the Chemical Composition and Crystalline Structure of Fish Bone Cured in an Acetic Acid Solution
2002 年 31 巻 p. 9-17
詳細
2002 年 31 巻 p. 9-17
The calcium intake should be adequate to prevent osteoporosis. The Japanese often eat fish, and small fish whose bones can be eaten are an important source of calcium. However, there have been only a few studies on fish bones, and fish bones are not efficiently used in the diet at present. To enable more efficient use of fish bones, we immersed the bones of horse mackerel in an acetic acid solution and evaluated changes in the crystallinity of bone apatite and in the inorganic components. Raw or steamed horse mackerel bones were immersed in a4% acetic acid solution for 120h. The crystal structure of bone apatite was measured by an X-ray diffraction analysis and the inorganic components were measured by ICP-AES. The crystallinity of fish bones immersed in the acetic acid solution showed a negligible change after 4h, but the amorphous part increased after 24h. Among the inorganic components, calcium, phosphorus, magnesium, and manganese rapidly decreased early after immersion. This decrease in such inorganic components as calcium, despite a negligible change in the crystallinity of bone apatite in the early stage of immersion, suggests the presence of calcium phosphate other than apatite in horse mackerel bones. When the fish bones were heated before immersion, the crystallinity of apatite was improved. Even after immersing the heated bones in the acetic acid solution, the amorphous part increased, while the apatite structure remained and inorganic components were difficult to elute. The softening of fish bones after their immersion in the acetic acid solution may be due to the elution of calcium phosphate that did not crystallize as apatite, with subsequent disintegration and elution of the crystalline apatite. Therefore, the vinegar solution used for immersing the bones contained inorganic substances eluted from the bone, and its use as a source of calcium would be suitable for increasing calcium intake.
