Fish skin is one of marine byproducts potential for alternative source of collagen. This study
investigated the effectiveness of alkaline and acetic acid pretreatment on the characteristics of
collagen from skin snakehead fish. The concentrations of alkaline pretreatment were 0.05; 0.1; 0.15
and 0.2 M for 2, 4, 6, 8, 10 and 12 hours, acetic acid concentrations were 0.05 M, 0.1 M, 0.15 M and
0.2 M for 1 and 2 hours. The experimental design used for alkaline and acetic acid pretreatment
was factorial completely randomized design. The result showed that the concentration of alkaline
0.05 M for 6 hours have significant effect on the elimination of non-collagen protein (p<0.05),
whereas for the optimum acetic acid at a concentration 0.1 M for 2 hours significantly different
on solubility and swelling. Extraction yields of collagen was 16%, with characteristics of whiteness
66.67%, protein content 96.21%, viscosity 10 cP, Tmax 159.9oC and glass transition temperature
78.55oC. The dominant amino acid composition were glycine (27.11%), proline (13.87%) and
alanine (12.58%). Functional groups collagen from skin snakehead fish has β-sheet structure
which is a characteristic of collagen.