Heat Interaction Between α-Lactalbumin, β-Lactoglobulin and Casein in Bovine Milk

When the concentration of casein in milk is reduced, there is an increase in the amount of ~-lactalbumin and /3-1actoglobulin recovered after heating. However, an increase in the concentration of whey protein decreases the amount of whey protein recovered. In whey the addition of/3qactoglobulin had no significant effect on the recovery of a-lactalbumin or /3-1actoglobulin after heating, but in milk addition of /3qactoglobulin decreased the amount of aqactalbumin and j3-1actoglobulin recovered after heating. This shows that casein facilitates the interaction of aqactalbumin and /3-1actoglobulin, and supports the view that t~-casein, flqactoglobulin, and a-lactalburain are involved in complex formation when milk is heated. Since the addition of a-lactalbumin to milk or to whey has no effect on the recovery of/3-1actoglobulin, it follows that the concentration of fl-lactoglobulin plays an important role in determining the degree of complex formation.