Abstract:

The degreasing of Ictalurus punctatus bone and the preparation of CMC active calcium from degreased fish bone through thermal soaking in a mixed acid made up of citric acid and malic acid were studied in this work. The effects of soaking temperature and time, mixing ratio for malic acid and citric acid, total acid amount and fish bone granular size on calcium yield were examined. The optimal procedure for degreasing Ictalurus punctatus bone was soaking in 5% aqueous NaOH solution for 6 h, and the total calcium content after the degreasing was 30.38%. The optimal conditions for the preparation of CMC active calcium were determined to be: mixing ratio for malic acid and citric acid, 1:2; total acid amount, 15 g/100 mL; material granular size, 120 mesh; soaking temperature, 100 ℃; and soaking duration, 60 min. A calcium yield of 87.13% was obtained under such conditions.

Key words: Ictalurus punctatus bone, CMC active calcium, degreased bone meal