Manufacture and use of dairy protein fractions.

Fractionation of the mixture of proteins found in milk and whey to form pure, individual dairy protein fractions might allow individuals with special nutritional needs to tailor their diet to improve health. Ion exchange process chromatography was examined for this purpose using selective elution to release separately the proteins bound from whey and produce several protein fractions. Alternatively, bound proteins were released all at once to make a whey protein isolate. Prototype beverages containing these proteins were examined for clarity before and after thermal processing. Beverages containing whey protein isolate were clear at pH 2-7 before heating, but only beverages at pH <or= 3.0 were clear after thermal processing (88 degrees C, 120 s). Beverages at higher pH were made clear after heating by addition of food-grade lauryl sulfate, which prevented aggregation of the denatured proteins formed during thermal processing. Alternatively, thermally processed clear beverages at pH 3-7 were possible using the whey protein glycomacropeptide. Because of the balance between sweetness and acidity, beverages with a pH greater than carbonated soft drinks and juices (pH 2.5-3) might remain palatable using less sugar. Development of high-protein low-carbohydrate beverages might provide health benefits for individuals suffering from diabetes, obesity, and hypercholesterolemia, especially when these beverages contain dairy protein fractions known to be high in essential amino acids and branched-chain amino acids.