OPTIMIZATION OF CHICKEN SKIN GELATIN EXTRACTION BY RESPONSE SURFACE METHODOLOGY

Traditional gelatin is mainly derived from the skins and bones of pork and cow.In recent years,due to the growing number of religious believers,the use of traditional gelatin is strictly restricted,so it's urgent to find a substitute for traditional gelatin now.Chicken skin contains abundant collagen,which not only canmeet the needs of religion people,but also improve the resourceutilization rate and economic benefit.The effect of NaOH concentration,NaOH treatment time,HCl concentration and extraction temperature on the gel strength of gelatin was investigated through single factor experiments.On the basis of single factor experiments,the Box-Behnken center combination experiment and response surface analysis were used to optimize the extractionconditions for chicken skin gelatin,and the regression model between gel strength and NaOH concentration,NaOH treatment time,HCl concentration and extraction temperature was built.The effect of those factors and their interactions on the gel strength.wasexplored by the analysis of the significance of the model.The results showed that the influence of NaOH concentration,NaOH treatment timeand extraction temperature on gelatin gel strength were all more significant,while HCl concentration and interaction of factorswere not significant.The optimum conditions were obtained through theverification text which were showed as follows:the concentration of sodium hydroxide was of 0.2 mol/L,the sodium hydroxide treatment time of 0.8 h,the concentration of hydrochloric acid of 0.6% and the extraction temperature of 55.0℃.Under these optimal conditions,the gel strength of gelatin was up to 396.6±4.0 g,which was significantly increased by 65% than pork skin gelatin (240.0 g).The present method will provide a theoretical basis for the development of new gelatin.