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

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Abstract
When the concentration of casein in milk is reduced, there is an increase in the amount of .alpha.-lactalbumin and .beta.-lactoglobulin recovered after heating. An increase in the concentration of whey protein decreases the amount of whey protein recovered. In whey the addition of .beta.-lactoglobulin had no significant effect on the recovery of .alpha.-lactalbumin or .beta.-lactoglobulin after heating, but in milk addition of .beta.-lactoglobulin decreased the amount of .alpha.-lactalbumin and .beta.-lactoglobulin recovered after heating. This shows that casein facilitates the interaction of .alpha.-lactalbumin and .beta.-lactoglobulin, and supports the view that .kappa.-casein, .beta.-lactoglobulin and .alpha.-lactalbumin are involved in complex formation when milk is heated. Since the addition of .alpha.-lactalbumin to milk or to whey has no effect on the recovery of .beta.-lactoglobulin, it follows that the concentration of .beta.-lactoglobulin plays an important role in determining the degree of complex formation.