The development of effective natural carrier systems, which solubilize, protect and maximize the bioavailability of the ingested nutraceuticals, for promoting human health, remains challenging. The structural and physicochemical properties and the high nutritional value of milk proteins makes them excellent carrier systems for nutraceuticals [1]. The novel use of proteins as vehicles for lipophilic nutraceuticals raises important questions regarding the bioavailability of the entrapped lipophilic nutraceutical. To examine these questions, we focused on vitamin D3 (VD3) loaded within re-assembled casein micelles (rCM) as a model system, and 0% fat yoghurt (the most widely consumed nonfat milk product) as a model food. In vitro gastric and duodenal digestion of the VD3 loaded vs. empty rCM was performed to study casein proteolysis and VD3 bio-accessibility. SDS-PAGE analyses of digesta revealed that the micelles undergo enzymatic degradation in the stomach and enter the small intestine as casein peptides irrespective of their loading with VD3. A large scale (94 healthy volunteers) double-blind placebo-controlled clinical trial was performed to examine whether the bioavailability of vitamin D3 would be affected by its delivery in protein nanoparticles, rather than in the fat, and in its absence. The results of this single high dose ingestion trial indicated that the bioavailability of VD3 in the protein based nanoparticles in the absence of fat did not significantly differ (p>0.1) from that in fat. Overall, this work provides pioneering evidence that protein-based nano-vehicles present an excellent alternative to fat for delivery of hydrophobic nutraceuticals in foods.
1. Livney YD: Milk proteins as vehicles for bioactives. Current Opinion in Colloid & Interface Science 2010, 15(1–2):73-83.
yifat@tx.technion.ac.il
