A study on amino acid composition and distinctive traits of collagen isolated from the skin and bone of an endemic pearl mullet species, Alburnus tarichi (Güldenstädt, 1814)

In this study, acid soluble collagen was extracted from both the skin (ASC-S) and bone (ASC-B) of pearl mullet Alburnus tarichi (Güldenstädt, 1814), and a comprehensive characterization was conducted, which included determining their amino acid profiles. This study represents the first-ever utilization of this particular species as a source of collagen. Notably, both ASC-S and ASC-B, extracted from the skin and bone of pearl mullet, exhibited glycine as the predominant amino acid, along with substantial levels of proline, hydroxyproline, alanine, and glutamic acid. In terms of dry weight percentages, ASC-S yielded 7.7%, while ASC-B yielded 2.5%. Additionally, Fourier transform infrared spectroscopy (FTIR) confirmed that both types of collagens were in their natural integrated state, while X-ray diffraction (XRD) analysis verified that the collagen in both skin and bone maintained their helical structures. UV-Vis spectra showed significant absorptions at 230 nm for the examined collagens. Furthermore, scanning electron microscope (SEM) examinations revealed the porous and fibrous nature of both ASC-S and ASC-B. The amino acid composition, as determined by UV–Vis and FTIR results, categorizes the extracted collagens as type I collagen. Overall, these findings suggest that collagen isolated from pearl mullet has the potential to serve as an alternative source of vertebrate collagens, with promising applications in various industries, including dietary, medical, and pharmaceutical.