<![CDATA[Background: Skipjack tuna (Katsuwonus pelamis) bone, an abundant fishery byproduct in Indonesia, contains protein and collagen with potential as an alternative collagen source for pharmaceutical and cosmetic use. Ethanol extraction is comparatively simple and more environmentally friendly than acid- or enzyme-based methods. Objective: This study aimed to determine the yield and physicochemical characteristics of collagen extracted from skipjack tuna bone using ethanol. Methods: Bone powder was macerated in 95% ethanol (1:10) for 72 hours, with solvent replacement every 24 hours, followed by concentration using a rotary evaporator. Yield, moisture, and ash content were determined gravimetrically; functional groups were identified by FTIR; protein content was measured by the Lowry method using a BSA standard curve. Results: Extraction yield was 9.76%, moisture content 1.01%, and ash content 0.036% — all within the gelatin quality reference SNI 8076:2014 (maximum moisture 16%; maximum ash 3.25%), used as a benchmark given the absence of a dedicated fish-bone collagen standard. FTIR spectra showed absorption bands for NH (3458.37, 3010.88 cm⁻¹), CH (2854.65, 2226.01 cm⁻¹), C=O (1743.65 cm⁻¹), and C-N (1462.04 cm⁻¹) groups, consistent with collagen structure and indicating the product had not been denatured into gelatin. The BSA standard curve showed a low coefficient of determination (R² = 0.518), so the sample's protein content could not be reliably determined from this curve. Conclusion: Ethanol extraction of skipjack tuna bone yielded a physicochemical profile meeting the available gelatin quality reference, with FTIR groups consistent with collagen structure. Protein quantification requires an improved calibration curve in future work.]]>
