## 3 Results and Discussions
### Color of Bio-Calcium and calcined Powders  
Bio-cal-A possessed a higher value of lightness (L* value) than Bio-cal-H and the calcined samples (\(p<0.05\)) (Table 2). The slightly higher creamy whitish color of Bio-cal-A could be a result of the removal of meat residue as well as the blood during the alkaline treatment of salmon bone. For Bio-cal-A and Bio-cal-H, during the drying process, carbonyl compound-related products were formed via lipid oxidation and could undergo a non-enzymatic browning reaction with the proteins, peptides, and amino group of the free amino acid retained in the bone powders. This resulted in the increased yellow color obtained in the bio-calcium powders as indicated by the greater positive b* values. Both bio-calcium powders had low redness (a* value). A similar trend was reported by [PERSON] et al. [25] in which bio-calcium powders from pre-cooked tongol (_Thununus tanggool_) and yellowfin (_Thununus albacores_) tuna bone had higher yellowness than their calcined counterpart.  
For the calcined samples, an increase in lightness (L*) was observed in both Cal-A and Cal-H when calcination time increased from 6 to 9 h. Similarly, the increases in *\(\Delta\)C were also observed. It should be noted that the L* value of Cal-H powders (69.49 \(\pm\) 0.04) was less than that of Bio-cal-H powder (98.84 \(\pm\) 0.08). The darker color could result from the dark grey color of the unburnt carbonaceous residue that may be trapped inside the porous structure of the fish bones during the calcination process. The result corresponded with the large quantity of organic constituents present in the Bio-cal-H powder as shown in Table 1. For a longer calcination period, the aforementioned carbonaceous particles could be further removed, which resulted in an increment of the L* value to 80.68 \(\pm\) 0.01. On the other hand, this observation was less pronounced in Cal-A powders. The result illustrated the impact of the alkaline pre-treatment and calcination process on the color of both the resulting bio-calcium and calcined bone powders.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Chemical Composition** & **Bio-Cal-A** & **Bio-Cal-H** & **Cal-A (6 h)** & **Cal-H (6 h)** & **Cal-A (9 h)** & **Cal-H (9 h)** \\ \hline Moisture (\%) & 4.82 \(\pm\) 0.07 \({}^{4}\) & 7.81 \(\pm\) 0.04 \({}^{*}\) & 0.27 \(\pm\) 0.00 \({}^{b}\) & 0.45 \(\pm\) 0.01 \({}^{c}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) \\ Protein (\%)\({}^{*}\) & 12.07 \(\pm\) 0.18 \({}^{b}\) & 20.90 \(\pm\) 0.06 \({}^{c}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) \\ Fat (\%)\({}^{*}\) & 0.03 \(\pm\) 0.01 \({}^{b}\) & 1.70 \(\pm\) 0.01 \({}^{c}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) \\ Ash (\%)\({}^{*}\) & 82.78 \(\pm\) 0.25\({}^{b}\) & 69.59 \(\pm\) 0.57 \({}^{a}\) & 99.73 \(\pm\) 0.05 \({}^{a}\) & 99.55 \(\pm\) 0.32 \({}^{a}\) & 99.99 \(\pm\) 0.00 \({}^{a}\) & 99.97 \(\pm\) 0.00 \({}^{a}\) \\ Hydroxylproline (mg/g) * & 5.07 \(\pm\) 0.01 \({}^{b}\) & 14.79 \(\pm\) 0.02 \({}^{c}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) & 0.00 \(\pm\) 0.00 \({}^{a}\) \\ TBARS (mg