Application of membrane technologies to bovine Ricotta cheese exhausted whey (scotta)

Bovine Ricotta cheese exhausted whey (scotta) is the final by-product of two consecutive cheese-making processes, with still a strong organic content; lactose was the main component (about 3.73 g 100 g−1). The total protein content was low (about 0.39 g 100 g−1), consisting of non-protein-nitrogen (almost 50%), whey proteins mostly in the denatured state, and abundant soluble peptides (nearly 1 g L−1). A membrane fractionation system composed of two ultrafiltration and one nanofiltration steps was investigated, testing different combinations of membranes and operational parameters, to separate residual proteins and peptides and recover lactose. Due to both fouling phenomena and protein-membrane interactions, a complete separation between whey proteins and peptides was not achieved. However, the application of only one ultrafiltration step, followed by nanofiltration, allowed separation of both one pure fraction, including whey proteins and peptides, and of another one in which 80% of the original lactose was concentrated.