Comparison of methods for the isolation of active α-lactalbumin in Chinese buffalo milk

With methods of fat centrifugal separation, isoelectric precipitation, iron salt precipitation and calcium precipitation, the α-lactalbumin in Chinese buffalo milk was isolated, and its activity and recovery were analyzed, while keeping the purity.When the purity of the isolatedα-lactalbumin exceeded 90%, its activity ratio and recovery reached to 44.68% and 21.06% respectively, by the use of 0.04% iron salt at pH4.5～4.7.While the referred activity ratio and recovery were 64.00% and 13.23% respectively with the use of 0.005% iron salt at pH7.0.Calcium salt precipitation gave a pretty high activity ratio of α-lactalbumin, but it brought the problem of a low purity, which made it deprecated to isolate the α-lactalbumin that demanding higher purity in active isolation.