Whey proteins: involvement in ricotta production and possible source of bioactive peptides

This doctoral thesis is focused on the protein composition of bovine whey. The study is divided mainly on two parts, since two different aspects were considered. Whey is the liquid remaining following the precipitation and removal of milk casein after cheesemaking. Whey is used in the dairy industry to produce Ricotta cheese. The whey samples, used in this work, were provided by an industry that produces daily Ricotta. In the first part, we reported the preliminary analysis of whey samples (total proteins quantification, major proteins identification) and then we focused on the main whey protein: β-lactoglobulin. We tried to estimate the amount of this protein in each sample using a specific software and an ELISA assay and to correlate its concentration to the yield production. In the second part, we studied the bovine whey as a possible source of proteins or peptides with nutritional and biological effects. There are a lot of information on the major whey proteins, β-lactoglobulin, α-lactalbumin, serum albumin and immunoglobulins, and their benefits to human health; for this reason we turned attention to the minor proteins. Some peptides, obtained by an enzymatic hydrolysis, were next used for some in vivo experiments in order to assess their hypothetical biological activity. The results showed that some of the peptides tested on different cancer cell lines may inhibit cell proliferation.