Effect of the Extraction Methods on the Physicochemical Characteristics of Collagen Derived from Tilapia (Oreochromis niloticus) Skin

Collagen from the skin of Oreochromis niloticus (Tilapia; TS) has gained visibility due to its extraction from waste materials from slaughterhouses, reducing environmental impacts, and because it is biodegradable, biocompatible, and nontoxic. The aim of this work was to evaluate the impact of two extraction methods on the physicochemical characteristics of collagen from TS for pharmaceutical and biomedical applications. The obtained TS was analyzed for its proximate composition. Two types of extractions were conducted using a 23 factorial design: acidic extraction (COL) and acidic extraction using pepsin (pCOL). The characterization of collagen was performed using rheological analyses, Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), circular dichroism, and scanning electron microscopy (SEM). The acid extraction method was effective in obtaining collagen both with and without pepsin. The proximate composition of the raw material showed results consistent with those of previous studies, highlighting the quality of collagen for use in pharmaceutical formulations. The extraction COL yielded more than pCOL, with both yields being close to 10%. The denaturation temperature of the collagen was above 32 °C, confirmed by DSC, TGA, and circular dichroism analyses, which is favorable for the intended applications. XRD revealed that the supramolecular structure of the type I collagen was preserved. Raman spectroscopy confirmed the presence of hydroxyproline and characteristic collagen amides, with the pCOL6 extraction showing greater stability. Structural differences between COL5 and pCOL6 were observed in the SEM micrographs, suggesting the potential for future applications in the pharmaceutical and biomedical areas.