Caprine and bovine cheese whey valorization: high-pressure processing for α-lactalbumin fractionation from whey concentrates

High-pressure processing was applied ( HPP ) on bovine (sweet and acidified) and caprine (acidified) cheese whey concentrated ( CWC ) by membranes, to obtain α-lactalbumin ( α-La ) enriched fractions. HPP treatment (600 MPa, 4 min) provoked in both bovine CWC high β-Lg precipitation (>80 %), leading to an α-La enriched fraction with a good balance between α-La yield and purification degree (>55 % and >80 %, respectively). Overall, HPP treatments of CWC led to values of α-La yield and purity lower to those obtained under similar conditions with bovine native concentrate whey. However, acidification of bovine CWC before HPP slightly influenced performance parameters (α-La yield, α-La purification degree and β-Lg precipitation degree). Under the same working conditions, acidified caprine CWC provided high values of α-La yield (94.88 %) but low α-La purification degree, due to undesirable β-Lg aggregation and precipitation, as confirmed by the marginal effects of pressure on the free thiol groups.