Integrating selective precipitation of ▫$alpha$▫-lactalbumin into a whey valorisation cascade

In the Balkans, and probably elsewhere, whey from small dairies, especially acid whey, still poses an environmental challenge. Despite recent advances in whey processing technology, whey is still largely treated as waste or ends up in biogas plants. Due to its high lactic acid content, acid whey cannot be concentrated by conventional drying or used directly in food. However, it contains several valuable components that can be converted into products with high added value. For this purpose, a valorisation cascade was developed, part of which is the extraction of lactoferrin and lactoperoxidase from acid whey or sweet whey. The remaining whey was concentrated and used for the acidic precipitation of α-lactalbumin. In small-scale laboratory experiments, a purity of α-lactalbumin of 72.9 % and 24.8 % was achieved, when isolated from acid whey and sweet whey, respectively. The isolation procedure was then demonstrated on a pilot scale, using 70 L of acid whey, which yielded 220 g of wet isolate of α-lactalbumin with a purity of 78.1 % and a high lysine (11.1 %) and leucine (10.0 %) content. The remaining whey fraction could be used in various fermentation processes or other applications.