Study On The Extration Of Hydroxyapatite And Collagen In Ionic Liquid From Bighead Carp Scales

Fish scales consist mainly of hydroxyapatite(HA)and collagen,HA and collagen have the wide of applications in medical science and food field.It not only avoids the waste of resource,but also reduces the pollution of environment.In this paper,the choline chloride/glycerol ionic liquid was synthesized and used to dissolve the scales of bighead carp.We talked about the effect of dissolution temperature,time,solid to liquid ratio on dissolution rate of collagen,finally,we found out the best conditions by orthogonal experiment.In addition,we investigated the effects of ethanol content on the collagen deposition and the amount of 5%(w/v)NaOH solution on the purity of HA.The extracted HA and collagen were characterized by Fourier transform infrared,thermogravimetric,scanning electron microscopy,ultraviolet,differential scanning calorimetry,X ray diffraction,grain size analysis.Meanwhile,the hemolysis of choline chloride/glycerol and extracted HA was investigated,and the influence of recyclable ionic liquid on the extraction efficiency of HA and collagen.The results showed that the best conditions for dissolving fish scale with choline chloride/glycerol ionic liquid were as follows:the dissolution temperature was 70?,the dissolution time was 2.5 h and the solid-liquid ratio was 1:15(w/w).The optimum addition of ethanol was 1:9(v/v),under this condition,the extraction rate of collagen was 11.67%.The optimum addition of NaOH solution was 1:5(w/v),under this condition,the extraction rate of HA was 47.67%.In addition,it was proved that the extracted collagen was a pure product,and had good three surround spiral structure,fiber columnar structure.The heat shrinkage temperature was 65.02 ?,the thermal decomposition temperature was 275.82 ?.The particle size of HA was not uniform,the HA appeared to micron-sized and nanometre particles.Hemolysis test data showed that the HA and chloride/glycerol ionic liquid had good blood compatibility.In addition,by the recovery and reuse of choline chloride/glycerol,the results showed that the extraction ratio of collagen was 13.12%,which increased compared with before the recovery.But the stability of three surround spiral structure of collagen declined.Finally,we prepared the collagen and composite films with the extracted collagen and HA,these two kinds of films showed the condition of uniform transparent,glossy,soft.The collagen film and composite film are similar to the food packing film in appearance and the break elongation,water vapor transmission rate,transmittance meet the requirements of the PVDC plastic film.