Optimization of gelatine extraction from grass carp (Catenopharyngodon idella) fish skin by response surface methodology

To establish the optimum gelatine extraction conditions from grass carp fish skin, response surface methodology (RSM) was adopted in this study. The effects of concentration of HCl (%, A), pre-treatment time (h, B), extraction temperature (°C, C) and extraction time (h, D) were studied. The responses were yield (%) and gel strength (g). A = 1.19%, B = 24 h, C = 52.61 °C and D = 5.12 h were determined as the optimum conditions while the predicted responses were 19.83% yield and 267 g gel strength. Gelling and melting points were 19.5 °C and 26.8 °C, respectively. Moreover, grass carp gelatine showed high contents of imino acids (proline and hydroxyproline) 19.47%. RSM provided a powerful tool to optimize the extraction parameters and the results may be adapted for industrial extraction of gelatine from grass carp fish skins.