|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1999 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1998 : ¥1,400,000 (Direct Cost : ¥1,400,000)
With the increase in the percentage of the elderly, the deficiency of calcium intake, which is a cause of osteoporosis, has become an issue. However, in Japanese traditional cooking, small fish is eaten as a whole including the bones, and this is considered to be effective as a means of dietary calcium intake.
This study was carried out to clarify the relationship between changes in physical properties of fish bone caused by marinating in vinegar and heating, and changes in the bone composition responsible for these physical changes. Softening of fish bone cured in an acetic acid solution or heated in various solutions water was evaluated by the sensory tests and various measurements, and changes in protein and inorganic components, which are primary components of fish bone, were examined by physical and chemical techniques.
Changes in the physical properties and components of fish bone after curing in an acetic acid solution were studied. The hardness of horse mackerel vertebra decrease
d in a short period after curing in an acetic acid solution. In this process, high percentages of calcium, phosphorus, and magnesium were eluted from bone, but little protein was eluted, suggesting that elution of inorganic components is involved in the softening of marinated bone. When fish bone was heated in various solutions (water, acetic acid solution, vinegar solution, green tea infusion), the hardness decreased with the duration of heating in all solutions with associated elution of protein. Bone heated in an acetic acid solutions showed marked decreases in hardness, more protein was eluted than by heating in water, and calcium was eluted. When raw bone was immersed in an acetic acid solution for a long period, the peak of apatite crystals observed in raw bone disappeared with the appearance of non-crystalline areas, suggesting changes in the cystallinity of bone apatite. Fish bone was heated in various solutions, and the cystallinity of bone apatite was studied. In all solutions, the X-ray diffraction pattern of bone apatite resembled that of hydroxy-apatite itself.
Thus, we consider that structural changes in collagen, a protein that constitutes bone, and bone apatite are causes of the reduction in the hardness of bone. Less