in bioavailability, but in all other cases the level of vitamin D in
the blood plasma was more than 50% higher than when mice
were fed vitamin D alone.
The ability of β-lg to improve bioavailability was linked
to the integrity of the two specific binding sites. Heating β-lg
destroys one of the sites, and Yang, et al. observed a corresponding step-wise decrease in the ability of heated β-lg to improve
vitamin D bioavailability in mice.
A research team from Canada and France reported that
complexing vitamin D with β-lg also improves its stability
during storage at 4 ˚C and exposure to UV light (Diarrassouba,
et al. 2014).
Fat globules in raw milk are surrounded by a membrane containing a complex mixture of polar lipids, which are ideal building
blocks for microcapsules called liposomes. Butter manufacture
produces a byproduct called buttermilk, which is rich in milk fat
globule membrane components such as phosphatidyl choline,
phosphatidyl ethanolamine, and sphingomyelin.
Liposomes consist of one or more concentric bilayers of
polar lipids enclosing an aqueous solution. They can house
polar bioactives in the aqueous regions, nonpolar bioactives in
the bilayer regions, or even a combination of polar and nonpolar bioactives within the same structure.
A New Zealand-China collaboration recently investigated
the potential for milk-derived liposomes to protect and deliver
FIG. 3. Oxidative stability of lipid encapsulated
in a NEST emulsion or a
control emulsion i.e. a
conventional protein-stabilised emulsion with
the same composition as
the NEST emulsion. Oxidation was measured via
the lipid hydroperoxide
assay (left y-axis) and as
headspace propanal (right
FIG. 4. 3-dimensional structure of the whey protein β-lactoglobulin,
showing two bound vitamin D3 molecules.
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