The effect of soaking time in acetic acid solution to the physical characteristics of gelatin from nila fish (Oreochromis niloticus) skin

Nila fish (Oreochromis niloticus) skin is one of fish waste from fish fillet industry which observe as source of gelatin. The aim of this research to observe the effect of soaking time in acetic acid solution (0,05 M) to the physical characteristics of gelatin nila fish (Oreochromis niloticus) skin. The treatment of soaking time (1, 2, 3, 4 and 5 hours) in acetic acid solution 0,05 M for demineralization process before extraction and drying process. The physical characteristics included viscosity, ash content, pH and colour. Viscosity of gelatin from soaking time (5 hours) and ash content from soaking time (1 hours) was significantly affect, while pH did not significantly affect. The colour of gelatin analyzed based on L*, a*, b* colour space were also describe the lightness. Gelatin molecule were analyzed through Fourier Transform Infrared Spectroscopy (FTIR) which had similar characteristics as collagen molecule.