Fish bones and scales are good sources of gelatin. However, high mineral content in bones and scales often lead to low quality gelatin with high percentage of ash. Therefore, pre-treatment with acid prior to gelatin extraction is necessary. Black tilapia (Oreochromis niloticus) bones and scales were subjected to Hydrochloric (HCl) acid of 0.6 M to 1.4 M for 0 to 32 hr. The suitable pre-treatment conditions were determined using percentage of ash removed and loss of protein from the samples. Results obtained indicate, 99.86 % and 99.84 % of ash can be removed from bones and scales, with 1.4 M HCl (32 hr) and 1.0 M HCl (10 hr), respectively. Further analysis with UV-Vis revealed that, excessive protein breakdown starts to occur at 1.0 M (32 hr) and 0.6 M (12 hr), in bones and scales, respectively. The data suggest using pre-treatment conditions lower than the above to avoid protein loss which may lead to low gelatin yield.
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