| In this thesis crude collagen peptides was preparated from cod skin by muti-strainfermentation. The molecular weight of distribution the collagen peptides was determined byHPLC. Using ultra-filtration, the crude collagen peptides were separated into four differentmolecular weight segments: CSPⅠ（<1kDa）、CSPⅡ（1~3kDa）、CSPⅢ（3~5kDa）and CSPⅣ（5~10kDa）. Through color reaction of Woessner method，the four molecular weightsegments were collagen peptides indeed. And the antioxidant activities of the four molecularweight segments were tested in vitro.By comparing fishy flavor and degree of hydrolysis of fermentation liquor, the optimalcombination and adding ratio of the microbes were selected. The resulted showed that theoptimal combination and adding ratio of the microbes was JF0Y3: Brewer’s yeast: H-2=2:1:1, fermentation time was30h. On this fermentation condition，the fermentation liquor hadthe maximum hydrolysis rate of46.12%, with almost no fishy flavor.The molecular weight distribution of the cod skin collagen peptides was determined byHPLC. By single factor experiment and Orthogonal test analysis, the optimumchromatographic conditions been investigated. The resulted showed that the optimalchromatographic conditions were trifluoroacetic acid: acetonitrile: water0.05:30:70, the flowrate1.0mL/min, column temperature25℃. On the optimal fermentation condition, themolecular weight distribution of cod skin collagen peptides was mostly less3kDa after30hfermentation, which accounting for66.92%of the total.The antioxidant activity of the four molecular weight segments, including DPPHradical, hydroxyl radical and superoxide anion scavenging was tested in vitro. The resultsshowed that the antioxidant capacity of the four molecular weight segments was higher thanthat of VC. The removal of DPPH, OH and O2-showed consistent, namely the smallermolecular weight the higer scavenging ability: CSPⅠ（<1kDa）>CSPⅡ（1~3kDa）>CSPⅢ（3~5kDa）>CSPⅣ（5~10kDa）. |
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