Characteristics of Biocalcium from Pre-cooked Skipjack Tuna Bone as Affected by Different Treatments

Biocalcium (Bio-Ca) from pre-cooked skipjack tuna bone was prepared using several treatments. Cleaning by high pressure water jet cleaner (CB), followed by alkaline treatment (AlB) could remove remaining meat and lipids, thereby increasing levels of Ca and P. This was confirmed by scanning electron microscopy with energy dispersive X-ray spectroscopy, in which Ca and P contents on bone surfaces were more increased (p<0.05). Defatting using hexane was able to reduce thiobarbituric acid reactive substances values and fishy odor intensity. Bleaching using sodium hypochlorite and hydrogen peroxide resulted in the increase in whiteness (L*-value) with decreases in redness (a*-value) and yellowness (b*-value). Fishy odor intensity of Bio-Ca markedly decreased with the coincidental decreases in volatile aldehydes, ketones and alcohols. Bio-Ca still contained collagen with imino acid content of 179 residues/1000 residues. Thus, individual treatment pro-foundly affected properties and fishy odor of Bio-Ca from pre-cooked skipjack tuna bone.