Acid and Pepsin Soluble Collagens from Skin By-product of Red-bellied Pacu (Piaractus brachypomus): Extraction and Comparative Characterizations Towards Finding Substitute to Bovine and Porcine Collagen

This investigation focused on the sustainable valorization of red-bellied pacu (RBP) skin towards finding an alternative to bovine and porcine collagen. Acid-soluble collagen (ASC, 45.8 ± 0.7%) and pepsin soluble collagen (PSC, 57.8 ± 1.9%) were successfully extracted from RBP skin and comparatively elucidated their characteristics and in-vitro fibril-forming potential. The extracted collagens were characterized as type I collagen and confirmed the well-preserved triple-helical configuration by sodium dodecyl sulphate polyacrylamide gel electrophoresis and Fourier transform-infrared spectroscopy analysis. Both ASC and PSC exhibited relatively better thermo-stability, and the denaturation temperatures were found to be 35.5–35.29 °C by differential scanning calorimetry analysis. Both collagens displayed higher (p ≤ 0.05) solubility at low NaCl concentrations. The extracted ASC and PSC showed the same degree of fibril-forming capacities and confirmed well-defined fibril morphologies. Overall, the results showed the possibilities of effectively exploring RBP skin as a potential alternative source for realistic and safe collagen for food, nutrition, pharmaceutical, and other applications.