Study On Technology Of Casein Glycomacropeptide Production By Enzymolysis Casein

Casein Glycomacropeptide (CGMP) is produced by chymosin (or pepsin) cleavaging of κ-casein between Phe105-Met106that contains64amino acid.CGMP has a variety of biological functions. But amount of lactose and whey protein prevent the development of production CGMP from whey on large scale. This paper has studyed the process of pro-ducing Casein Glycomacropeptide from the dissolution of casein, chymosin hydrolysis conditions, primary separation, refine of CGMP and determinate products composition.The relationship between concentrate of sodium hydroxide, casein dissolved contents and the CGMP yield are reseached.The best solution conditions were:NaOH0.16mol/L, concentration of casein dissolved6g/100mL.With single factor results of experiments, the enzyme hydrolysis conditions effect on κ-Casein glycomacropeptide was selected with Minitab software. It was showed that the principal factors were hydrolysis time, temperature, pH, and [E]/[S]. The optimum enzyme hydrolysis conditions was optimized by Design Expert system:time80min, temperature42.5℃, pH6.28,[E]/[S]270U/g. The yield of CGMP was17.91mg/g casein under the op-timal conditions.In the part of separation and purification CGMP, the influence of different flocculants, the differents between flocculation and isoelectric precipitation methods, the best condi-tions of ultrafiltration and ion exchange resins were studied. The experiment results showed that the effect of flocculation with chitosan, potassium aluminum sulfate, aluminum sulfate were better than other flocculants, but worse than isoelectric precipitation methods. Single factor experiment of ultrafiltration indicated that the best conditions were:pressure0.276Mpa, Stirring speed400r/min, pH7.5. A sort of anion exchange resin D280screened from kinds of ion exchange resins. The optimum conditions of purificating CGMP by ion exchange resin were:injection volume1/10BV (bed volume), pH7.5,0.lmol/LNaCl used to eluting non-target materials,0.5mol/L NaCl to eluting CGMP and1.0mol/L NaCl to re-generate ion exchange resin. Eluting volume were2BV, elution rate1BV/h. The eluting condition was good proved by SDS-PAGE which has a single band of CGMP.3CGMP samples with different purity were obtained with spray-drying method, and the related physical and chemical characteristics were detected according to national stan-dards. The results showed the degree of glycosylate and purity of CGMP was quite high, and the hygiene indexes reached national standards.