Study On Extraction Of Collagen, Gelatin And Hydroxyapatite From Scales

Fish scales is one of the raw materials to extract collagen, gelatin and hydroxyapatite, which is rich in collagen and calcium, phosphorus, and etc. In order to improve the comprehensive utilization of scales, this paper has researched the process of extracting collagen, as well as gelatin and hydroxyapatite from bighead carp scales.Optimize the production of decalcification and use magnetic stirring to decalcify the fish scales. The optimum conditions of decalcification were as follows:mass fraction of citric acid9.79%, stirring time72min, ratio of solid to liquid1:23g/mL, stirring speed900r/min. Under this condition the decalcification rate reached93.39%.After decalcification, using pepsin assisted by ultrasonic to extract collagen from fish scales, the optimum conditions were determined as:the pH1.5, ultrasonic power300W, ratio of solid to liquid1:20g/mL, enzyme concentration5%, ultrasonic time40min, extraction time5h, extraction temperature25℃, Under this condition the extraction rate was56.24%.Optimize the production of extracting gelatin from fish scales by adopting thermodynamic method. The optimum conditions were as follows:ratio of solid to liquid1:10g/mL, extraction time7.20h, extraction temperature87℃. Under this condition the extraction rate reached61.23%.Use residue fish scales extracted gelatin as raw material and prepare hydroxyapatite by calcination at high temperature. HAP calcinated at different time and temperature were analysed by IR and XRD. The optimum conditions were as follows: calcined temperature900℃, calcined time2h. the ratio of calcium to phosphorus was1.62.Taking performance comparison between the extracted collagen and gelatin. Analysis the structure of collagen and gelatin by UV, IR and XRD. Determine both the type and content of amino acids of the collagen and gelatin by amino acid analysis. Meanwhile, the properties of collagen and gelatin, such as film-forming, water absorption, oil absorption, denaturation temperature, emulsifying property and foamability were studied systematically. The results showed that the triple helix structure of gelatin has been damaged seriously and lose biological activity. The glycine, hydroxyproline, proline content of gelatin was higher than those of collagen. The content of methionine, lysine, phenylalanine increased significantly while the content of glutamic, alanine and arginine were decreased, Denaturation temperature of collagen was28.3℃. Both collagen and gelatin had bility of film-forming, however, the collagen membrane was superior to gelatin film. The water absorption, oil absorption of collagen were better than those of the gelatin, while the foamability and emulsifying properties of gelatin were better than those of the collagen.