The Application Of Collagen From Fish Skin In Restructured Fish Technology

With the progress of science and advcancement of people's lives, the requirement of comsumers for fish products are increasing dromatically, and the high-grade fish products with nutrition balanced, unique flavor, and which are easy to cook are needed particularly. Using some low-value fish or minced meat from processed fsh, then adding a small amount of accessory to stick fish mice together effectively, which called restructed fish products, this method could not only enrich the varity of aquatic product, but also increase economic efficiency. In this paper, different extraction methods of collagen from amiurus nubulous skin were explored, effect and mechanism of collagen in restructed fish product were probed further into research, and the research contents were as follows:1. The optimal process of extracting collagen by hot water through response surface method was material liquid ratio 1:13,70?,6 h, and the optimal conditions of collagen extraction yield could reach to 96.25%; the optimal process of extracting collagen by alkali solvent through orthogonal design optimization was material liquid ratio 1:10, added 1.5%Ca(OH)2,70?, extraction conditions under 9 h, and the extraction rate of collagen was 79.67%; the result of extraction by salt solvent was designed through orthogonal design optimization:material liquid ratio 1:30, added Na2SO4 25 g/L and NaOH 8 g/L,50? under 2 h, the optimal conditions of collagen extraction yield of 98.73%.2. The extraction by alkali,salt,hot water,acid and enzymatic to collagen was analysed and compared, and collagen was explored from molecular to microscopic structure by means of UV spectrum scanning, Fourier transform infrared chromatography, SDS-PAGE, thermal denaturation temperature, scanning electron microscopy. The result showed that five kinds of collagen have a similar maximum absorption peak at 230nm; collagen by acid, enzymes, hot water was determined to be collagen type I by SDS-PAGE patterns,which also retained good protein structure, and the highest gel stability goes to collagen by hot water, while collagen extracted by alkali and salt were found to be in the form of the polypeptide; the thermal denaturation temperature of collagen by alkali, hot water, salt, acid and enzymatic solvent was 70?,70?,50?,29.8? and 22? respectively. The resluts displayed that different extraction methods of collagen have different influence for amino acid composition, rheological properties, thermal denaturation temperature and microstructure.3. Collagen from different extraction was explored the impact to fish in this part of experiment by taking advantage of carp surimi as raw material. Gel strength, TPA texture characteristics (hardness, elasticity, gumminess, chewiness),water-holding power and whiteness were explored to comprehensive assess quality of fish products.4. The results showed that:compared with the blank sample, the synthetical mark of collagen by alkali solvent raised 86%, collagen by acid solvent raised 63%, collagen by salt solvent raised 26%, collagen by enzymatic raised 71%, collagen by hot water raised 72%. It is evident collagen obtained by different extraction methods played different role on the quality of restructed fish.5. Combining power,protein dissolution ratio, TCA-soluble peptide content, paraffin tissue section and SDS-PAGE were used to explore the mechanisms of collagen in restructured fish. It was obivious to find that the mechanism of different collagen showed difference:alkali-soluble collagen and surimi gels not only form more disulfide bonds, but also activate endogenous transglutaminase (TG) in fish and generated more non-disulfide valence bond, therefore enhanced the network structure in gel; acid-soluble collagen enhanced the gel structure by the formation of more disulfide bond in the gel; more disulfide bonds were found by adding enzyme-soluble collagen during the process of surimi gel; and water-soluble collagen played an important role in inhibiting protein degradation during gel process.6. Utilizing orthogonal optimization design that the highest gel strength by adding 0.1% collagen,0.9% chitosan, and 0.3% konjac flour respectively, which showed the best quality of the products.Under this condition, it's found that gel properties of restructured fish products with compound accessory was better than blank sample.In this paper, the process of extracting collagen by alkali, salt and hot water were explored from Amiurus nubulous skin, and the physicochemical property of collagen were comprehensive analysised; the effect of collagen in the restructured fish were mutual compared, and the mechanism of action were detected. Finally, the best collagen as additives, and compounded with polysaccharides to generate the high quality of restructured fish steak.