Yield, Viscosity, and Gel Strength of Wami Tilapia (Oreochromis urolepis hornorum) Skin Gelatin: Optimization of the Extraction Process

A factorial design and response surface methodology were used to optimize the extraction process of tilapia skin gelatin (Oreochromis urolepis hornorum). The concentrations of NaOH (0.15%-0.35%) and H2SO4 (0.15%-0.35%), the extraction temperature (40 degrees C-60 degrees C), and the extraction time (3-15 h) were independent variables. Response variables were yield (%), viscosity (mPa.s), and gel strength (g). The NaOH (%) and H2SO4 (%) concentrations had significant influences (p<0.05) on viscosity and gel strength, while the extraction temperature (degrees C) and the extraction time (h) showed significant influences (p<0.05) on all dependent variables. Increasing the temperature and extraction time provided higher yields with a reduction in the gelatin viscosity and gel strength. Tilapia fish skin can be used as a source for production of gelatin.