Study On Preparation Technology Of Casein Glycomacropeptide And The Exploitation Of Special Food For Phenylketonuria Patients

Casein glycomacropeptide(CGMP)is released from ?-casein during the milk-clotting process in cheesemaking.CGMP is a kind of peptide which has many physiological functions and it can be used in function food and health products.CGMP has no Phe in its amino acid composition makes it suitable for nutrition in cases of phenylketonuria.Processes with anion exchange resin and chitosan have been used to separate CGMP from whey powder.Pilot-scale study on separation treatment of CGMP was carried out with the optimized process.We tested the content of CGMP in product by high performance liquid chromatograph and developed special food for phenylketonuria patients according to the detection results.The main results are presented.Detection method based on high performance liquid chromatography technique which is suitable for CGMP quantitative determination was established.Other proteins in whey powder were removed by isoelectric point precipitation and cation exchange resin.Results showed that isoelectric point precipitation method with simple operation can get better results.The precipitation pH was 5.1.Ion exchange resin and chitosan were used to separation CGMP from whey powder.CGMP with a higher purity was prepared by ion exchange method.In addition,ion exchange method with simple operation might be of potential for industrial production because the separation medium can be reused.Pilot-scale study on separation treatment of CGMP was carried out by ion exchange methods.CGMP product with higher purity was prepared by ion exchange resin with dynamic method.The process route was investigated.After removing the impurity from 0.04g/mL whey powder solution at pH 5.1 by centrifugation,supernatant pH was adjusted to 3.9 as sample.Then sample solution was added in chromatography column which filled with the same volume anion exchange resin.CGMP eluted from anion exchange resin by sodium chloride solution which concentration was 0.6mol/L.The eluent was desalted and concentrated by ultrafiltration membrane with molecular weight cut off 6000 u.The results showed that 11.7g CGMP was obtained from 40 L whey powder solution.The yield of CGMP was 0.73 gram per 100 gram whey powder with 36 L ion exchange resin.The purity and sialic acid concentration of CGMP product was 80.4% and 15.9% respectively,and phenylalanine proportion was 0.28%.In this project,CGMP was used as protein source to design some special foods for phenylketonuria patients such as nutrition powder,protein powder,jelly and milk tablet.In order to meet the nutritional requirement of patients,fructo-oligosaccharides,taurine and L-carnitine were added in nutrition powder and protein powder.The phenylalanine content was 0.0524% and 0.25% in nutrition powder and protein powder respectively.The established process route which obtained high purity and sialic acid concentration CGMP product has simple operation.These results can provide reference for the industrial production of CGMP and product development.