Optimization Of Fish Protein Hydrolysis Process And Functional Properties Of The Hydrolysates

Fish protein power is a rich and green resources,and fish protein is high quality,but fish protein power is mainly used as feed,this causes the resource waste.In this paper,fish protein powder was hydrolysed by protease to prepare fish peptides,hydrolysis conditions were optimizated.And the antioxidant activity,solubility,foaming and emulsifying properties of the hydrolysates were determined.The main purpose is to explore the possibility of application of fish protein hydrolysates in the food industry.Firstly,fish protein powder was hydrolysed by Alcalase 2.4L and papain,effects of substrate and enzyme concentration,hydrolysis time,pH,and temperature on the degree of hydrolysis(DH)were studied respectively.On the basis of single factor experiment,the hydrolysis conditions were optimized by Response Surface Methodology.The optimum conditions for Alcalase 2.4L were:substrate concentration 3%,enzyme concentration 2.5%,time 6h,pH 8.04,temperature 60?.Under these conditions,DH of the hydrolysate was 19.11%,NSI was 95.67%.Secondly,Alcalase 2.4L and papain were used to hydrolyze fish protein by double-enzyme two-step hydyolysis.DH of double-enzyme hydrolysis product had no significant difference with the hydrolysate by Alcalase 2.4L,but was much higher than the hydrolysate by papain.Ascorbic acid and soybean isolate protein were used as controls to evaluate the antioxidant activity and functional properties of hydrolysates comprehensively.The result showed that the antioxidative activity of hydrolysate hydrolyzed first Alcalase 2.4L then papain was the best,and solubility of the hydrolysate hydrolyzed first Alcalase 2.4L then papain showed high solubility over a wide range of pH 2 to 10,hydrolysates obtained by Alcalase and papain had better foaming and emulsifying properties.Further study result showed that concentration and pH of hydrolysates solution affected the founctional properties strongerly.?-cyclodextrin,sugar,and citric acid were applied on high solubility hydrolysates,respectively.Sensory analysis showed the mixed of citric acid and sugar had a better taste.