Optimization of Pre-treatment Conditions for Producing Gelatin from Chicken Skin by Response Surface Methodology

The objective of this study was to optimize the chemical alkaline-acid pre-treatment conditions of chicken skin for gelatin extraction. The effect of concentration of NaoH and hydrochloric acid in three levels for each one (0.05, 0.53 and 1 N) as independent variables on response variables including extraction yield, viscosity, gel strength and melting point were evaluated using a faced central composite design of response surface methodology. The results showed that gel strength and melting point parameters were influenced simultaneously by the concentration of NaoH and hydrochloric acid, while the yield of the extraction was only related to the concentration of the NaoH and the viscosity was dependent on the concentration of hydrochloric acid. The concentrations of 1N of NaoH and 0.05 N hydrochloric acid were predicted as common pre-treatment optimal conditions for the production of gelatin in the chicken skin, in this case, the extraction yields were 3.8 %, the viscosity was 81.4 cp, the strength of the gel (Bloom) was 485.4 g and melting point was 42.8° C.