Study On Preparation And Characterization Of Collagen From Carp Scales

The resource of freshwater fish of China is rich,and the proportion of freshwater fish further processing is increasing.Nowadays the waste materials left from the processing,such as the scales,the bones and so on haven't been utilized sufficiently,which result in the wast of resorce and the pollution of environment. The scales contain rich collagen,which has a bright future in the area of medicine,food and so on.The full use of this resorce of collagen in the development of product with high additional value not only can help widen the path of the utilization of the aquatic products,but also can improve the comprehensive economic benefit of aquatic processing enterprises.Aquatic collagen study of China is still at an initial stage in primary,and there is still little further study on extraction procedure and the physical and chemical properties,which has restricted the development of product from freshwater fish collagen.In this paper,the preparation of acid soluble collagen(ASC)and pepsin-solubilized collagen(PSC) and parameters optimization have been studied.The results show that Na2CO3 can remove the waste protein of the scales effectively.The best condition can be abtained when the concentration of Na2CO3 is 0.5M,material to liquid ratio is 1/20,the processing time is 6h,and maximum removal rate can be achieved after 3 times of removement.The mineral matters are moved by EDTA complexing method.The single factor experiment show that when the concentration of EDTA is 0.3M ,the material to liquid ratio is 1/60,the time of processing is 12h,and the most ideal effect of decalcification can be abtained after 3 times of repetation.Ultrasonic extraction can improve the effect of decalcification and the removement of other protein.The best effect of decalcification can be abtained when the processing time is 20min on the ultrasonic frequency of 40Hz,however, that of removement of other protein can be abtained when the processing time is 10min on the ultrasonic frequency of 60Hz.The result of ASC extraction experiment show that the most optimum effect is abtained when the acetic acid concentration is 0.8M,the material to liquid ratio is 1/60,and the maximum extraction rate is received after 4h.The result of PSC extraction experiment show that the maximum extraction rate is abtained when the aceticacid concentration is 1.5M,material to liquid ratio is 1/40,the pepsin concentration is 3%,the extraction temperature is 20℃,the processing time is 24h.The structural characteristics of the collagen samples preparared are identification by SDS-PAGE, infrared analysis,amino acid analysis.The result show that ASC and PSC are typical typeⅠcollagen,similar with pigskin collagen on infrared spectra and subunit composition;however,ASC,PSC and pigskin collagen are different on the amino acid composition in different extent,which result from the different source of material and the extraction method.Based on the study above, the physical and chemical properties,such as thermal denaturation temperature, dissolve ability and emulsification property are studied systematically.The result show that the thermal denaturation temperature of ASC is 30～35℃,and of PSC is 28～35℃;PSC is better than ASC on solubility, emulsification property,but worse than ASC on solution viscosity, water absorption ability,oil-absorbing capacity and foamability.The rheology properties of solution take an important part in the collagen chemical and physical properties,which is meaningful for the usetage of ASC and PSC in the areas of food and medicine.The result show that in the shear rates chosed, the solution of ASC and PSC perform as the pseudoplastic of typical non-newtonian fuild.In the same degree of concentration,the viscosity of the collagen solution ranged as ASC> PSC> gelatin; shear rate, the factors of temperature,pH and so on affect the properties of the solution of ASC and PSC significantly;when the concentration of the solution of collagen is 0.6%,ASC and PSC perform as fluid,not gel;the behavioral elasticity is enhanced and the viscosity behavior is weakened.