Increased loading of vitamin D2 in reassembled casein micelles with temperature-modulated high pressure treatment

Native casein micelles were treated (incubated) with vitamin D-2 at different hydrostatical pressures (0.1, 200, 400, and 600 MPa) and temperatures (10-50 degrees C) in order to load the vitamin. Pressure induced the release of alpha(s)-, beta- and kappa-casein and calcium from the micelle into the soluble phase. During the pressure stable reassembled micelles were created due to a structural rearrangement of hydrophobic interactions between the hydrophobic domains of the caseins and vitamin D-2. Treatment at 600 MPa and 50 degrees C increased the loading of vitamin D-2 per casein from 2.2 +/- 0.2 mu g/mg (native sample) to 10.4 +/- 02 mu g/mg. The reassembled micelles presented an average hydrodynamic diameter of 272 +/- 10 nm and contained 8.1, 10.3 and 0.8 mg of alpha-, beta- and kappa-casein, respectively, per 100 mg casein. (C) 2014 Elsevier Ltd. All rights reserved.