In-vitro self-assembly and antioxidant properties of collagen type I from Lutjanus erythropterus, and Pampus argenteus skin

The fish processing by-products are rich source of various novel and valuable biomolecules such as collagen and gelatin. Herein, we have extracted and purified collagen from the skin of two different marine fish species-crimson snapper (Lutjanus erythropterus) and silver pomfret (Pampus argenteus). The processing of these fishes produces huge quantities of by-products such as skin, fins, and bones. So, the extraction of collagen will be promising for the value addition to their by-products. Finally, the yield is moderately high viz. 13% (crimson snapper) and 7.5% (silver pomfret) on dry weight basis, respectively. The isolated proteins were characterized by different physicochemical techniques like FTIR, CD, SDS-PAGE, Zeta potential analyzer, SEM, and EDX. The denaturation temperatures (T-d) as determined by CD was 34.54 degrees C and 33.58 degrees C for crimson snapper and silver pomfret, respectively. The T-d is close to the mammalian collagen and hence, they serve as better alternative to mammalian collagen. The collagen from both the sources had lowest solubility at a basic pH (8-10), and lower ionic strength while higher solubility in acidic pH (1-5), and higher ionic strength. Further, the fibrillogenesis process was studied to understand the effects of temperature and ionic strength on collagen in vitro self-assembly. Collagen self-assembly is advantageous in making collagen-based gels for cell culture, and biomedical applications. In addition, the antioxidant activities of collagen and collagen hydrolysates prepared by enzyme (trypsin) were examined by DPPH, FRAP, NO and TAP antioxidant assays. The hydrolysates showed outstanding antioxidant activities as compared to native collagen solution. The result shows that fish waste is the potential and sustainable sources of collagen where its applications are not limited by religious conflicts and threats of various transmittable diseases.