Stability of vitamin D3 encapsulated in nanoparticles of whey protein isolate

Vitamin D-3 was entrapped in whey protein isolate (WPI) nanoparticles prepared by different calcium concentration and aggregation pH. Its stability was investigated in presence of air for 7 days. Residual of vitamin D-3 in nanoparticles was higher compared to control samples (water, native WPI and denaturized WPI). Presence of calcium in composition of particles resulted in formation of compact structure and inhibition of oxygen diffusion in particle. Lower concentration of vitamin D-3 (280 mu g/ml versus 560 mu g/ml) had negative effect on residual amount of vitamin. The loss of vitamin D-3 during storage time was described by a second order reaction. The results illustrate that these nanoparticles can be used in clear or non clear beverages as enriching agent. (C) 2013 Elsevier Ltd. All rights reserved.