Impact Of Casein Glycomacropeptide On Functional Properties Of Whey Proteins

Whey protein has many physiological functions and unique nutritional attributes. CMP was mainly derived from k-casein hydrolysate by rennet. Impact of CMP on functional properties of whey proteins was the reason for its limited uses. In the present study, optimal hydrolysis conditions of casein, the isolation and purification condition of CMP, the mechanism of CMP acting on the functional properties of whey proteins were all studied.The effect of pH, temperatures, protein concentration, salt concentration on the gels hardness and springiness of different whey proteins was studied. Electrophoresis was used to confirm the composition of acid whey protein and sweet whey protein.Using orthogonal experiment, technology conditions of using rennet hydrolyzing casein to produce casein glycomacropeptide were studied, and the optimum enzyme hydrolysis conditions were as follows: pH6.5, hydrolysis temperature 50℃, 90min, E/S 2%, the SA concentration was 7.447mmol/L.TCA precipitation, the optimal conditions for the ultrafiltration were determined. the method is simple and practicable without whey protein denaturation, the purification of CMP was 86.96%.The heat-induced gel of whey protein, with addition of different ratio of casein glycomacropeptide (CMP) dispersed in water at neutral pH, was studied. As the ratio of CMP to whey protein ratio was increased, the gel strength of samples decreased rapidly, and the formation of intermolecular disulfide bonds was blocked to certain degree. Scanning of electron microscope indicated that the gels with a high proportion of CMP have a coarse structure with larger pores and a loose network of crosslink compared with pure acid whey protein gels.