Study On The Large-scale Extraction Key Technology And The Activity Protection Method Of The Bovine Immunoglobulin G

Pre-extraction by cold ethanol and trimeric sodium phosphate,concentration by ultrafiltration,sterilization,as well as protective agent of thermal denaturation and gastric acid of bovine immunoglobulin were mainly researched by using bovine colostrum as raw material. The Establishment of the key technology of large-scale production and protection process was of great significance for exploiting bovine colostrum and developing the functional colostrum food.1.Pre-extractionWhen the extracting agent was cold ethanol,the process parameters as ethanol concentration,pH value and ionic strength were studied by single factor experiment and orthogonal test.And the test indexes were the purity and the recovery rate of IgG.The best process parameters were that ethanol concentration was20%,pH value was6.7,ionic strength was0.06mol/kg.In this condition,the purity was39.28%and the recovery rate was79.32%.When the extracting agent was trimeric sodium phosphate,the process parameters as the addtion of trimeric sodium phosphate,pH value and temperature were studied by single factor experiment and orthogonal test.And the test indexes were the purity and the recovery rate of IgG.The best process parameters were that the addtion of trimeric sodium phosphate was0.5%,pH value was4.0,temperature was45℃.In this condition,the purity was33.74%and the recovery rate was82.31%.2.The ultrafiltration processThe ultrafiltration process used hollow-fiber ultrafiltration device and3types of hollow fiber membrane module to concentrate the IgG.The suitable membrane module was determinated by the pruity,the recovery rate of IgG and the ultrafiltration flux. The process parameters as the dilution ratio,the ultrafiltration pressure and the ultrafiltration temperature were studied by orthogonal test.And the test indexes were the purity and the recovery rate of IgG.The best process parameters were that the dilution ratio was2,the ultrafiltration pressure was0.10MPa,the ultrafiltration temperature was30℃.In this condition,the purity was53.03%and the recovery rate was82.23%.3. SterilizationAfter the pasteurization(65℃,30min) and the high temperature short time sterilization(HTST)(75℃,15s),the retention rate of IgG were90.68%and86.23%.The quality of both was close,but the production efficiency could be effectively improved by HTST.4.The thermal denaturation protective agent formulationThe factor of the quadratic rotary combination design in the experiment of the thermal denaturation protective agent formulation was the addtion of3types of protective agent.The retention rate of IgG had been detected after water bath(95℃).The best formulation was that the addition of glutamic acid was0.22%,the addition of maltose was7%,the addition of glycerol was12.5%.In this condition,the retention rate of IgG was90.91%.5.The digestive test in vitroThe protection experiment in alimentary canal was using ultrasonic combined with film dispersion method.And the test index was the embedding rate.The process parameters as the soy phospholipid-cholesterol quality ratio,the ultrasonic extraction temperature and the ultrasonic extraction time were studied by orthogonal test.The best process parameters was that the soy phospholipid-cholesterol quality ratio was2:1,the ultrasonic extraction temperature was30℃and the ultrasonic extraction time was15min.In this condition,the embedding rate was44.16%.The digestive test in vitro of IgG liposomes was prepared with adult simulated gastric fluid(pH=2.0),infant simulated gastric fluid(pH=4.0) and simulated intestinal fluid(pH=6.8).And the retention rate of IgG were42.04%,77.23%and75.02%.The retention rate of the adult simulated gastric fluid group had improved significantly.On the other hand,the group of infant simulated gastric fluid and simulated intestinal fluid did not need the protective agent.