Studies On Modification Techniques And Biological Activity Of Cod Skin Protein Peptides

Cod is one of China’s important Marine economic fingerling, an annual processingcapacity of up to400,000~500,000t. About28,000~40,000t cod skins can be produced,95%of which were processed into feeds, only less than5%were used to extract collagen orto be processed into clinical medical food. The optimal preparation conditions of cod skinpeptides by compound enzyme, selecting the best calcium source to chelate with cod skinpeptides and animal experiments for validating the physiological functions of the chelateswere stuied:(1) The optimum conditions was: the hydrolysis reaction occurred first with0.6%papain enzyme and35%substrate at70℃and pH6.0for3h, then with0.4%flavorenzyme and30%substrate at60℃and pH6.5for3h, with the hydrolysis degree reached25.87%. The study of molecular weight on cod skin peptides showed that the molecularweight was a continuous distribution, from10000daltons to30000daltons, which indicatedcod skin protein had been hydrolyzed into peptides.(2) The results showed that using activecarbon coupling with yeast had much more efficient to remove the bitterness and fishysmell of the the code skin peptides by compound enzyme. The optimal conditions were thatthe reaction occurred first with1.5%yeast at35℃and pH5.0for90min, then with2.0%active carbon at40℃and pH5.0for70min. Under the optimal condition, the hydrolysatesbitterness value was9.0and had little fishy smell with the recovery of protein at91.5%, theloss rate of peptide and free amino acid at4.68%and3.78%.(3) The results showed that theoptimal calcium was CaCl2, the chelation reaction between hydrolysates and CaCl2conducted for20min at25℃and pH7.0with a calcium/peptide mass ratio at0.3/3. Theresult of ultraviolet and infrared showed the products that calcium chelating with cod skinpeptides were different from the cod skin peptides.(4) the animal experiments resultsshowed that the calcium chelating with cod skin peptides was a good kind of high-qualitycalcium preparations which significantly increased mice bone mineral densities, and theeffects were better than the calcium carbonate.