Soluble Asian sea bass bone bio-calcium: characteristics, bioavailability across Caco-2 cells and fortification into apple juice

Soluble Asian sea bass bone bio-calcium (SBC) prepared using citric acid was characterised and examined for bioavailability. SBC showed lower calcium content (9.12%) but higher solubility (74.56%) in in vitro gastrointestinal tract system, compared to bio-calcium. Calcium bioavailability of bio-calcium across Caco-2 cells was higher than that of SBC. SBC showed slightly lower L*, b* and Delta E*-values with higher a*-values than that of bio-calcium. Fortification of SBC at various levels (0, 0.5, 1, 1.5 and 2%, w/v) into apple juice was also carried out. Apple juice fortified with SBC at various levels showed differences in pH, turbidity, brown colour and calcium content. The increased SBC levels resulted in lower pH, but higher turbidity, brown colour and calcium content. SBC fortification had no effect on likeness score for appearance, colour, odour and sandy mouthfeel. Nevertheless, flavour, taste and overall likeness of apple juice decreased when SBC added was increased. Calcium content of apple juice fortified with SBC up to 1% was increased by 6.13-fold with no sensory effects.