Gelatin is an important hydrocolloid which has been widely applied in the food industry for it’s unique properties. The aim of this investigation was optimization of the conditions of gelatin extraction from chicken deboner waste using response surface methodology and to compare physicochemical properties of the extracted gelatin with a commercial gelatin. Acid concentration (X 1 ), extraction temperature (X 2 ) and extraction time (X 3 ) were chosen for independent variables at 5 levels: for acid concentration 1.64 (1.636), 3, 5, 7 8.36 (8.364) %, for extraction temperature 53.1 (53.15), 60, 70, 80 86.8 (86.82?C) and for extraction time 1.95 (1.954), 4, 7, 10 12.05 (12.046) hr. Central composite design was adopted in the optimization of gelatin extraction from chicken deboner waste. Dependent variables were yield, gel strength, viscosity and lightness. For each of dependent variables one regression model was fitted. The analysis of variance indicated that the coefficients of linear (X 1 , X 2, X 3 ) and interaction (X 2 X 3 ) were highly significant ( P 0.01) and coefficient of quadratic (X 22 ) was significant (0.01 P 0.05) in yield model. The coefficient of quadratic (X 11 ) was highly significant in gel strength model. The coefficients of linear (X 1 ), quadratic (X 22 ) and interaction (X 2 X 3 ) were highly significant in viscosity model but coefficients of linear (X 3 ) and interaction (X 1 X 2 ) were significant. All the coefficients of linear (X 1, X 2 ), quadratic (X 11 , X 22 ) and interaction (X 1 X 3 ) were highly significant in lightness model. The predicted values of dependent variables under optimum conditions were yield of 10.40 %, gel strength = 526 gr, viscosity = 5.84 Cp and lightness = 70.117 that were obtained under the conditions of acid pretreatment with 6.73 % acid solution and hot water extraction at 86.8?C for 1.95 hr. Verification experiments were conducted under optimal conditions to compare predicted and actual values of dependent variables. Actual values repeated three times were yield = 10.10 %, gel strength = 520 gr, viscosity = 5.55 Cp, lightness = 68.215. Both actual and predicted values almost coincide each other. Therefore, the estimated response surface model was adopted for optimization of gelatin processing from chicken deboner waste. Other factors were measured about both of commercial and gelatin that was extracted under optimum conditions. The amount of protein in the commercial and extracted gelatin was, 86.20 and 85.67 %, the amount of lipid, 0.72 and 0.80 %, moisture percentage, 8.19 and 8.89 %, ash percentage, 4.15 and 4.41 %, gelatin content, 75.
