Study On Extraction And Properties Of Collagen And Its Polypeptide From Silver Carp Scale

In this study, silver carp scale was taken as the material to extract collagen by enzymatic hydrolysis firstly, and then collagen polypeptide was prepared from collage by microbial collagenase. Moreover, their important physics and chemistry properties were detected and analysized. This study was developed a feasible procedure for effective utilization of fish scale, which was helpful to utilize silver carp scale effectively. The research results were as follows:1. Pepsin, Papainase and Trypsin was tentatively used to extract collagen from silver carp fish scale, and the enzyme showing best performance was screened to optimize preparation procedure of collagen by orthogonal experimental design. The results showed Pepsin presented the highest yield of collagen from silver carp scale, and the optimum condition with yield rate of 56.8% was processed at 40℃and pH2 with 4% enzyme for 48h. The molecular weight of scale collagen was mainly ranged from 30.0KDa to 94.0KDa by SDS-PAGE. Analysis of amino acid elements indicated, in collagen extracted from silver carp scale, the highest proportion was Gly (glycine), Pro (proline) and Glu (glutaminic acid) took the second place, and Cys (cystine) and Tyr (tyrosine) showed the low content. All the above data are consistent with the property of standard collagen type I . Furthermore, the collagen viscosity decreased with the elevation temperature, and its emulsification capability was EAI with 5.44 m~2/g pro.2. Collagens polypeptide was prepared by microbial collagenase from scale collagen of silver carp. Orthogonal experimental design was used to optimize the preparation procedure. The result showed the yield rate reached the top at 40℃and ph7.5 for 6h. Seen from SDS-PAGE, the molecular weight of scale collagen polypeptide was mainly under 20.0KDa and obviously less than scale collagen. The result indicated collagen was degraded evidently by collagenase.3. The property detection of collagen polypeptide from silver scarp scale showed the sample took on hazel color with the feint fishy smells, and its isoelectric point (pI) was pH4.7, and the microbiology inspection accorded with the criterion for super full-cream milk powder. This polypeptide was demonstrated the ability to remove free radical with 15.89% of SA%, and its Minimal Inhibitory Concentration (MIC) was 1.0mg/mL and 0.5 mg/mL for Staphylococcus aureus and Escherichia coli, respectively.