Separation of alpha-Lactalbumin Enriched Fraction from Bovine Native Whey Concentrate by Combining Membrane and High-Pressure Processing

Whey exhibits interesting nutritional properties, but its high beta-Lactoglobulin (beta-Lg) content could be a concern in infant food applications. In this study, high-pressure processing (HPP) was assessed as a beta-Lg removal strategy to generate an enriched alpha-Lactalbumin (alpha-La) fraction from bovine native whey concentrate. Different HPP treatment parameters were considered: initial pH (physiological and acidified), sample temperature (7-35 degrees C), pressure (0-600 MPa) and processing time (0-490 s). The conditions providing the best alpha-La yield and alpha-La purification degree balance (46.16% and 80.21%, respectively) were 4 min (600 MPa, 23 degrees C), despite the significant decrease of the surface hydrophobicity and the total thiol content indexes in the alpha-La-enriched fraction. Under our working conditions, the general effects of HPP on alpha-La and beta-Lg agreed with results reported in other studies of cow milk or whey. Notwithstanding, our results also indicated that the use of native whey concentrate could improve the beta-Lg precipitation degree and the alpha-La purification degree, in comparison to raw milk or whey. Future studies should include further characterization of the alpha-La-enriched fraction and the implementation of membrane concentration and HPP treatment to valorize cheese whey.