Functional Characteristics Of Enzymatic Hydrolysate From Crayfish Shell And Development Of Snack Food

Crayfish is one of the important economic shrimps in China,and a large number of shrimp by-products are produced every year.As a kind of waste,shrimp by-products will cause certain pollution to the environment.Turning shrimp by-products into valuable is in line with the current environmental protection requirements of resource recycling.Shrimp shell is rich in protein,which is a good animal protein resource that has not been fully utilized.But up to now,there is a lack of research on the development of shrimp shell protein food at home and abroad.In order to make full use of shrimp shell waste and shrimp shell protein for systematic research,this topic prepared shrimp shell hydrolysate by six different enzymatic hydrolysis methods,namely: 1.Alkaline protease hydrolysis;2.Ultrasonic-assisted alkaline protease hydrolysis;3.Enzymatic hydrolysis with complex enzymes(papain and flavor enzyme);4.Enzymatic hydrolysis with complex enzymes(papain and neutral enzyme);5.Segmented enzymolysis(trypsin ? flavourzyme);6: Segmented enzymolysis(flavourzyme? papain).Freeze-dried powder was prepared by freeze-drying,and shrimp-flavored puffed food was prepared by using it.The main research results are as follows:(1)The amino acid content obtained by different enzymatic hydrolysis methods is different,and the shrimp shell protein obtained by the segmental enzymatic hydrolysis(trypsin?flavor protease)enzymatic hydrolysis is the best in the essential amino acid content and the ratio of essential amino acids to non-essential amino acids,Complex enzymes(papaya enzyme and flavor enzyme)followed.(2)From the results of scanning electron microscopy and Fourier infrared analysis,it is known that the lyophilized powders obtained from the six enzymatic hydrolysis methods have certain differences in microstructure and secondary structure.(3)Comparison of functional characteristics: the solubility(55.3±0.9%),emulsifying property(59.2±1.6%),emulsifying stability(112±2.5%)and water absorption(3.1±0.04 g/g)of the freeze-dried powder of complex enzyme(papain and flavor enzyme)hydrolysate are the highest;The freeze-dried powder of enzymatic hydrolysis(flavourzyme ? papain)has the highest oil holding capacity(130±1.9%).(4)Comparison of antioxidant activity: The DPPH free radical scavenging ability of freeze-dried powder of enzymatic hydrolysate(flavor protease ? papain)is the strongest,and the scavenging rate is(63.07±0.35)% when the concentration is 10 mg/ml;The total antioxidant capacity of freeze-dried powder of ultrasonic-assisted alkaline protease hydrolysate is the strongest,and the total antioxidant value is 33.41±0.44 U/ml when the concentration is 10 mg/ml;Freeze-dried powder of complex enzymes(papain and flavor enzyme)has the strongest hydroxyl radical scavenging ability,and when the concentration is10mg/ml,the hydroxyl radical scavenging rate is(75.43±2.89)%.(5)Single factor experiment of making shrimp-flavored leisure puffed products: when the ratio of wheat flour,glutinous rice flour and potato starch is 7:3:2,the content of shrimp shell freeze-dried powder is 3%,the slice thickness is 2 mm,the microwave power is 460 W,and the moisture content is 24.06%,the puffed rate of shrimp chips is the highest.(6)Response surface optimization experiment of shrimp-flavored leisure puffed products:microwave power 468 W,slice thickness 1.9 mm,freeze-dried powder addition 3.1%.Under these conditions,the puffing rate of shrimp chips puffed by microwave is 1.732.