Research on degreasing methods and physical- chemical characteristics with degreasing before and after of gelatin from silver carp skin

In order to explore whether silver carp skin was a kind of good sources of gelatin or not,and to obtain gelatin from silver carp skin with low- fat,the degreasing methods for gelatin were investigated,and the physical and chemical characteristics of the gelatin with degreasing before and after were compared.The basic ingredients of silver carp skin were comprehensive analyzed. The gelatin of silver carp skin was extracted by hot water. Then made degreasing treatments with four kinds of macroporous resins( D101,X- 5,XAD1180,AB- 8) by the way of static adsorption.The results were obtained as follows: silver carp skin were rich in protein and minerals and could be used as a kind of good sources of aquatic gelatin; The rate of degreasing can be reached at 78.94% ± 2.98%,the hydroxyproline content rose from 6.77% ± 0.09% to 7.17% ± 0.13% after treated with D101 in the gelatin solution when temperature was 40 ℃,resin amount was 10%.UV and FT- IR measurements of gelatin without degrease and gelatin with degrease were quite similar,and all of them showed maximum absorption peak at 221 nm.SDS- PAGE pattern indicated that both of them contained β,α₁ and α₂ chains. Gel strength of gelatin without degreasing was light higher than that of gelatin with degreasing.However,the viscosity of gelatin with degreasing was higher than that of gelatin without degreasing.Compared with the gelatin without degreasing,the contents of Ca,Mg and Zn in gelatin with degreasing were increased by 75.96%,284.13% and 2.68%,respectively,while the contents of Cu,Fe and Mn in gelatin with degreasing were decreased by 16.67%,48.11% and 15.56%,respectively.