| China is a major egg producing and consuming country,and the increase in egg consumption is accompanied by a mountain of waste eggshells,causing serious pollution to the ecological environment and a waste of resources.Research on the development and utilization of egg shells and under-shell membranes,which can be turned into treasures and increase the added value of eggs.In this project,the eggshell and eggshell membrane were successfully separated by studying shell and membrane separation technology;the de-membranated eggshell was ground into ultra-fine eggshell powder by ultra-micro crushing technology;and the extraction of hyaluronic acid as well as chondroitin sulfate was carried out from the eggshell membrane,and the following conclusions were obtained.(1)Research on eggshell and subshell membrane separation process.The orthogonal full implementation method was used to screen the conditions for the separation of eggshell and subshell membranes;and the response surface method was used to optimize the process parameters for the removal of residual eggshell from eggshell membranes by dilute hydrochloric acid.The results showed that the best shell membrane separation effect was achieved under the conditions of crusher running5s/time and crushing 3 times,with 58.72%powder yield,87.91%decalcification rate and a comprehensive score of 72.91;at 1g of crude eggshell membrane,20ml of hydrochloric acid volume,19min reaction time and 0.5mol/L hydrochloric acid concentration were used,at which time the decalcification rate could reach 89.21%.(2)Research on egg shell ultra-micro crushing process.The effects of different grinding jars on the ultramicrocomminution of eggshells were screened,and the conditions for the ultramicrocomminution of eggshells in planetary ball mills were optimized.The results showed that:the coarse powder was ultramicrushed at 180 min when the agate jar appeared to sink and adhere to the wall at the latest,the maximum specific surface area was 1962 m~2/kg,the minimum median particle size was 11.407μm,and the best grinding effect;the coarse eggshell powder was ultramicrushed at 150 min,the rotational speed was 425×g,and the ball to material ratio was 6:1,the maximum specific surface area of eggshell powder under this process condition was The maximum specific surface area of eggshell powder under this process was 2152.47m~2/kg.(3)Study on the process of extracting hyaluronic acid from eggshell membrane.Hyaluronic acid was extracted from eggshell membranes by enzyme extraction.The effects of different crushing methods on the extraction rate were compared,and the extraction process was optimized by orthogonal test method.The results showed that the best extraction effect was obtained from ultra-micro crushed eggshell membranes,followed by ordinary crushed eggshell membranes and the worst from uncrushed eggshell membranes.The optimal extraction process for the ultramicronized eggshell membrane was as follows:1 g of eggshell membrane dissolved in 30 m L of distilled water stock solution,p H 8,temperature 50°C,enzyme dosage 10000 U,and reaction time 4 h.Under these conditions,the extraction amount of hyaluronic acid in 1 g of eggshell membrane could reach 14.58 mg/g.(4)Process optimization study of chondroitin sulfate extraction from eggshell membranes.The chondroitin sulfate in eggshell membranes was extracted by alkali salt method using common crushed eggshell membranes as raw material,and the extraction process was optimized by designing a response surface test.The results showed that the extraction rate could reach 76.5%with 1g of eggshell film,15.5:1 material-liquid ratio,60℃extraction temperature,6:1 alkali-salt ratio and 8h extraction time. |
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