Study On Extraction Of Collagen From Tilapia Scale And Packaging Applications

Scales is the main byproduct of tilapia, and scales are rich in protein, considered as good raw materials of collagen and gelatin. Quite a number of scales were discarded and not fully used. In this paper, tilapia fish scales were used for the extraction of collagen, the enzyme hydrolysis of collagen protein peptide and applied it to the carp meat preservation. The main research contents are as follows:Firstly, HCl solution was used to demineralize the fish scale. The optimum processing technology of the demineralization was as follows: Concentration of HCl was 0.5 mol / L; Ratio of feed liquid, 1:17.5(w: v); Time of extraction, 1.5 h; Stirring speed, 100 r / min. The content of scale ash was 1.56%. This study used hot water to extract gelatin from fish scales. The optimum extraction conditions were founded to be 90℃ extraction temperature, feed liquid ratio of 1:14(w: v), p H 6, extraction time was 5 h. The obtained gelatin extraction rate was 84.67%, collagen purity is higher.Secondly, this paper studied the enzyme hydrolysis conditions of active protein peptide from the tilapia scales. Fish gelatin as raw materials, this article used neutral and alkaline and flavor protease to hydrolyze the collagen from scales. The optimum processing of protein hydrolyzed was determined: Neutral protease, enzyme concentration 5%, substrate concentration of 4%, p H 7.5, temperature of 50℃ and the reaction time 2h,the DH was 5.62%; Alkaline protease, enzyme concentration 7%, substrate concentration 8%, p H 9.5, temperature of 55℃, hydrolysis time 2.5 h, the DH was 22.41%; Flavor protease, enzyme concentration 5.5%, substrate concentration 8%, p H 6, temperature of 50.1℃, hydrolysis time 3 h, the DH was 61.18%. Composite enzymatic hydrolysis can reduce the cost of production; The molecular weight of 200~1000D was relatively more. The optimal combination of the compound enzyme enzymolysis is: the substrate concentration is 10%, p H 7.5, temperature of 50℃, first with neutral protease 0.15% reacted 3h, after adding alkaline protease 0.15% reacted 1h, at this time 200~1000D molecular weight content is 57.66%.Finally, this paper was studyed on the effects of coated gelatin and protein peptide from tilapia scales on fresh-keeping of crucian carp. Mixed gelatin and protein peptide, chitosan made coating film, coating on the surface of crucian carp fillets. The drop loss, p H value, total volatile basis nitrogen value, and total plate count were tracked and analyzed to comprehensively, judged the preservative effects of treatment with different coatings. Without treatment of carp shelf period was 5.5 days, the gelatin solution of carp shelf period for 7 days, the gelatin chitosan mixture processing carp shelf period of 7.9 days. The fish protein peptide chitosan blend processing can save 6.5 days.Experiment shows that gelatin and protein peptide has the feasibility and effect of preservation on fresh-keeping of fish.