Study On Preparation, Properties And Application Of Scale Collagen Peptide From Crass Carp

The resource of scale is rich in China,but it has not been completely used.In this paper,the preparation by enzymatic hydrolysis,properties and preliminary application of scale collagen peptide from freshwater fish Crass carp were studied.The basic and amino acid composition of 5 common freshwater fish(Grass carp,Crucian carp,Carp,Silver carp,Tilapia) scales were determined.The results indicated that freshwater scales were mainly composed of protein(50～75%) and inorganic substance.Acid processing and alkali processing were necessary to the preparation of scale collagen peptide.It can not only improve the extraction rate;but also can improve the purity and quality of collagen peptide.The optimal conditions of acid processing were:0.4mol/L HCl solution,substrate to solution 1:15,time 2h.The optimal conditions of alkali processing were:3g/L Ca(OH)₂ emulsion,substrate to solution 1:15,time 24h.The scale was basically composed of coarse collagen under these processes.Alkali proteinase was proved to have the best hydrolysis results when we use single-enzyme hydrolysis method to prepare scale collagen peptide.The optimal conditions have been found by response surface methodology as following: temperature 53.7℃,enzyme dosage 9280U/g,pH 11.2,concentration of substrate 5.73%,time 2.5h.Under these conditions,the SN-TCA was 64.77%and the content of amino acid was 10.23%.Complex-enzyme Hydrolysis method can remove the bitter taste and fishy smell of enzymolysis liquid.The optimal conditions of complex-enzyme Hydrolysis method were:using alkali proteinase first,the conditions were,temperature 53.7℃,enzyme dosage 4640U/g,pH 11.2, concentration of substrate 5.73%,time 2h.And then,using flavor enzyme,the conditions were,temperature 45℃,enzyme dosage 2400U/g,pH 6.5,time 2h.Under these conditions,the SN-TCA was 66.28%and the content of amino acid was 11.73%.Amino acid composition and molecular weight distribution of scale collagen peptide were determined.The results showed that:its amino acid composition was in line with the characteristics of collagen;its molecular weight distribution was wide,mainly concentrated in the 9275D(about 48%) and 2647D(about 37%).Some major functional properties of scale collagen peptide were determined.The results showed that scale collagen peptide had high water solubility,NSI was 99.9%;water adsorption was 23.4%under the conditions of time 30℃,relative humidity 60%;had a certain degree of water holding capacity; fat absorption was 4.97ml/g;had high foaming ability,but foam stability were poor;had strong hydroxyl radical scavenging activity,with the increasing of concentration of peptide solution,the scavenging rate was higher,but it did not show a simple linear relationship.Scale collagen peptide was added to cream to make collagen peptide skin cream.It founded that the different addition amount of collagen peptide did not influence the emulsification of skin cream;the more addition amount,the more exquisite of skin cream;but when the addition amount was more than 0.5%,there would be many small bubbles in the skin cream,and would take a long time to eliminate.Finally,0.5%was chose to be the addition amount of collagen peptide to skin cream,White color,fresh aroma,exquisite cream was made under this condition.The collagen peptide skin cream had good thermal stability,cold stability and Centrifugal stability.