Preheat-Treatment and Bleaching Agents Affect Characteristics of Bio-calcium from Asian Sea Bass (Lates calcarifer) Backbone

Purpose This study aimed to elucidate the effect of preheat-treatments and bleaching agents on molecular characteristics and bioavailability of obtained bio-calcium. Methods Bio-calcium from Asian sea bass backbone was prepared using different preheat-treatment methods (boiling at 100 degrees C for 30 min or autoclaving at 121 degrees C for 90 min). Subsequent bleaching was carried out using 2.5% sodium hypochlorite, followed by 2.5% hydrogen peroxide or using 2.5% hydrogen peroxide alone. Results Bio-calcium powder from autoclaved bone had higher calcium content (35.9 +/- 0.2%) than that produced from boiled bone (25.7 +/- 1.2%). Particle size of bio-calcium from autoclaved bone (16.71 +/- 16.71 mu m) was lower than that from boiled bone (52.85 +/- 43.16 mu m). Highest whiteness index (92.26 +/- 0.21) was observed for autoclaved bone bio-calcium when hydrogen peroxide alone was used as bleaching agent. FTIR study confirmed that Ca-hydroxyapatite was present in both bio-calcium from boiled and autoclaved bones but the amount was higher in the latter. Conclusion Boiling or boiling/autoclaving could be alternative pre-treatment for bio-calcium production to reduce chemical or alkali used and to soften the bone. However, solubility of autoclaved bone bio-calcium was lower than boiled bone counterpart. Enhancement of solubility is still needed to improve bio-availability of bio-calcium from Asian sea bass backbone. [GRAPHICS] .