Vitamin D3 cress seed mucilage -β-lactoglobulin nanocomplexes: Synthesis, characterization, encapsulation and simulated intestinal fluid in vitro release.

Vitamin D (VD) as an essential lipid-soluble active ingredient with numerous applications in food and pharmaceutical sectors; however, poor water solubility reduces its bioavailability significantly. Application of protein-polysaccharide complexes as a promising way to protect and trigger programmed release of bioactive molecules has established an optimal window in nutraceutical delivery systems. In this study, complexes of β-lactoglobulin (Blg) and cress seed mucilage (CSM) were used to retain VD at undesirable circumstances, such as acidic pH values. The interaction of CSM-Blg was studied by rheological tests and the best formulation was chosen for encapsulation of VD via crosslinking with calcium ions (2-10 mM). The results demonstrated that complexation protect VD at low pH values with the maximum encapsulation efficiency of 84.2 %. The in vitro study indicated that Blg-CSM-VD was more stable in simulated gastric fluid, and in turn VD was released in simulated intestinal fluid; the complexes treated with calcium ions had a slower release rate than normal complexes. The release trend of VD followed the diffusion-Fickian law and the principal interactions included hydrophobic, electrostatic and hydrogen bonding. The results indicated that Blg-CSM complexes can retain VD at acidic environment and induce sustained release, which brings about practical advantages for vitamin delivery in the food and pharmaceutical sectors.