Research On Preparation And Characteristic Of Collagen From Navodon Modestus Skins

In this paper, the preparation and characteristic of collagen from Navodon modestusskins were mainly researched. The pretreatment conditions and the best conditions of usingacid method, protease method and ultrasound-assisted acid method to extract collagen fromNavodon modestus skins were studied. Then obtained three types of collagen sample whichwere isolated from extracting solution. And the physicochemical property and antioxidantactivities of collagen samples were researched at last. The results were as follows:1. The content of collagen in fish skins was about14.85%, and the content of collagen intotal protein was about60.79%. The rusults were obtained by single factor tests: in0.1mol/Lthe sodium hydroxide solution containing1%hydrogen peroxide and3%sodium chloride,leaching treatment6hours later, the color of fish skin became milky white, about60%ofnon-collagenous proteins in fish skin were removed.2. The extraction rate of collagen was regarded as an index, the optimal conditions ofextracting collagen were obtained by single factor and orthogonal tests:(1) Acid method:After pretreatment, marinating the fish skin in0.3mol/L acetic acid solution, the ratio betweenfish skin and solvent was1:40, homogenizing the mixture6hours later, then leachingtreatment58hours. The extraction rate of collagen from fish skins was44.75%under thisconditions.(2) Protease method: After pretreatment, marinating the fish skins in pH3.0disodium phosphate-citric acid buffer, homogenizing the mixture12hours later, then addingin acid protease to hydrolyze. The conditions of enzymic hydrolysis were as follows: acidprotease1000u/g, the ratio between fish skin and solvent was1:5, reaction time25h. Underthis condition, the extraction rate of collagen from fish skins was57.95%.(3)Ultrasound-assisted acid method: After pretreatment, marinating the fish skin in0.3mol/Lacetic acid solution, the ratio between fish skin and solvent was1:30, homogenizing themixture6hours later. The extracting conditions of using ultrasound-assisted acid methodwere as follows：ultrasound power800W, on-time of the pulsed ultrasound3s and off-time3s,extraction time10min. The extraction rate of collagen from fish skins under above conditionswas67.84%. 3. The matter which extracted from Navodon modestus skins was collagen by analyzingthe ultraviolet absorption spectrum and infrared absorption spectrum. The denaturationtemperature of three types of collagen sample from fish skins were obtained by Ubbelodheviscosimeter method:19.96℃(acid method),18.66℃(protease method),19.34℃(ultrasound-assisted acid method). Under the same conditions the solubility of collagenextracted by protease method was the best through solubility tests.4. With the increasing of the concertration, the effect of the collagen on antioxidantactivities gets gradually stronger. The collagen which extracted by using protease method hadexcellent scavenging effect on superoxide anion free radical and hydroxyl radical andanti-lipid peroxidation. The collagen which extracted by using acid method andultrasound-assisted acid method had excellent scavenging effect on superoxide anion freeradical and hydroxyl radical. But on the anti-lipid peroxidation, the effect became inapparent.